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A Vox article about genetically engineered humans.

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Biotechnology has advanced so rapidly over the past few years that scientists can now edit the genomes of plants and animals with ever-increasing precision. Using new techniques like CRISPR/Cas9, researchers have already shown they can alter genes to create hornless cattle or mushrooms that don't brown easily.

But the really big question - the stuff of sci-fi - is whether we'll use genome-editing tools on people to wipe out heritable diseases or to enhance human capabilities. It's no longer a question of whether we'll be able tocreate "designer babies": The technologyis improving at a stunning pace. Instead, it's a question of whether we should. It's an ethics question, a policy question.

On Tuesday, the influential National Academy of Sciences released a 261-page report on this issue, titled "Human Genome Editing: Science, Ethics, and Governance." It's one of the most thorough looks yet at what's likely to be possible with new genome-editing techniques - and why scientists should tread carefully.

The report's recommendations are eyebrow-raising: In very, very limited cases, editing of viable human embryos should be allowed to go forward in the United States - a conclusion that's certain to prove controversial. In particular, the report argues, clinical trials to edit human sperm, eggs, and embryos should be permissible in cases where there's a high chance of preventing babies from being born with serious genetic diseases and no "reasonable alternatives" exist.

By contrast, the panel says editing embryos for human enhancement - say, making people stronger or more intelligent - should absolutely not proceed in the United States until there's much broader society-wide discussion of the thorny ethics involved, like the risks of exacerbating the gap between rich and poor. The report is an in-depth discussion of the issues at play here, so let's dig in.

The four big reasons we might want to edit the human genome

The report starts by taking stock of all the powerful biotech tools available today, from zinc finger nucleases to TALEN to CRISPR/Cas9. While the technical details vary, these techniques "can be used to make precise changes in the genome at a high frequency and with considerable accuracy." Here's a diagram showing how CRISPR/Cas9 works:

There are four big reasons why scientists might want to tinker with the genetic material of human beings in particular - ranging from least controversial to most controversial:

1) Basic research on human cells in a lab. This one's straightforward. A scientist takes cultures of human cells and uses, say, TALEN or CRISPR to tinker with the genetic code to figure out how our molecular processes actually work - or better understand what our genes do. Scientists might edit "somatic" cells (nonreproductive cell types like skin or liver cells) or "germline" cells (eggs or sperm). But these experiments would never produce viable embryos or modify living human beings.

This is basic, essential research that's not much different from what's been going on for decades, and the report argues that existing guidelines should be sufficient to govern these practices. Nothing too contentious here.

2) Clinical trials to edit somatic cells in living humans. Increasingly, however, scientists are also interested in using genome-editing techniques to treat diseases in humans. Last June, the National Institutes of Health approved the first-ever clinical trial to use CRISPR as a cancer treatment. Scientists at the University of Pennsylvania will take immune cells out of 18 cancer patients, edit the cells to make them more effective at targeting cancer, and then infuse the cells back into the patient to see what happens. (This trial is mainly intended to probe the safety of this technique.)

This sort of "gene therapy" will become more common as editing techniques improve. The NAS report cites a long list of potential applications down the road. An excerpt:

The panel argues that there aren't any hugely troubling ethical issues here, since this involves altering somatic (i.e., nonreproductive) cells, and the altered traits can't be passed on to offspring. The panel does, however, urge caution. Genome-editing techniques still aren't perfect, and they can sometimes misfire, leading to random mutations or other "off-target" effects in the edited cells. What's more, no one's yet been able to develop clear safety standards around what misfires are acceptable.

So, the report says, regulators at NIH will need to scrutinize proposals for gene therapy trials on a case-by-case basis. In general, it's safest to take a cell out of a patient and edit it (known as "ex vivo" treatment), because researchers can more easily check for off-target effects. By contrast, there are still plenty of technical challenges involved in editing cells directly inside a human body ("in vivo" treatment).

3) Editing sperm, eggs, and embryos to stop inheritable diseases. Okay, now we're getting to the controversial stuff. It's one thing to edit an adult's immune cells. If anything goes awry, the effects won't be passed on. It's another matter entirely to edit sperm, eggs, or embryos (known as the "germline") and create genetic changes that can be passed down from generation to generation. Now we're no longer talking about editing a single human. We're talking about editing humanity.

For now, the FDA and NIH are barred from approving research on editing human embryos, because of the potentially fraught social and ethical concerns involved. But other countries, like China and the United Kingdom, are moving forward with embryo editing, and interest is certain to grow. There are thousands of inheritable diseases caused by mutations to a single gene (like Huntington's). For many families, genome-editing may be the only way to prevent kids from being born with certain conditions.

So the panel tries to strike a balance here. It argues that the US government should allow clinical trials on editing sperm, eggs, or embryos - but only under very, very limited conditions. It should be done only to try to prevent "serious diseases" where there's a convincing link between the gene in question and the disease - and only when there are no "reasonable alternatives." The panel also urges rigorous oversight and a "continued reassessment of both health and societal benefits and risks."

The panel concedes that this recommendation is likely to prove contentious. Some people will find the idea of editing viable sperm, eggs, or embryos morally wrong. Others will note that concepts like "reasonable alternatives" and "serious disease" are left frustratingly vague. And still other researchers may find these guidelines so strict as to bar useful research. (More on this below.)

It's also not clear how widespread embryo editing would become even if US regulators did approve it. As the panel notes, there are still "major technical challenges to be addressed in developing this technology for safe and predictable use in humans." As a result, the panel predicts that we aren't likely to see much germline genome editing to prevent disease "in the foreseeable future."

4) Editing the human genome for "enhancement." Of course, if scientists could one day edit viable embryos to eliminate diseases, they could also conceivably edit embryos for enhancement. Stronger babies. Smarter babies. Babies born only with blue eyes. territory, basically.

The NAS report notes that this possibility raises all sorts of thorny issues. Would the use of genetic enhancement make inequality worse? Might it one day become so prevalent that enhancement becomes mandatory, like vaccines are today? Should parents have a right to improve their children through genetic modification? How far should regulations around genome editing go to respect religious and cultural discomfort? Are there risks we haven't even thought of yet? (Almost certainly.)

The report basically concludes that we haven't even begun to have a serious discussion around these issues, as a society. Nor do policymakers really understand yet what sorts of regulations and governance these techniques should require. As such, the panel recommends that "genome editing for purposes other than treatment or prevention of disease and disability should not proceed at this time."

But that's easier said than done. The report notes that the boundary between disease prevention and enhancement can often be hazy. Using genome editing to improve musculature for patients with muscular dystrophy might be okay. But what about improving musculature for people genetically disposed to be weaker than normal? Where do you draw the line? What about genetic editing to improve cholesterol levels? As such, the report notes, scientists and policymakers are going to have to think harder about what counts as "normal" and what is an "enhancement."

This report won't end controversy around human genome editing

Suffice to say, this report doesn't have all the answers for what's okay and what's not around human genome-editing - and it would be ridiculous to expect as much. This is a complex debate that will persist for decades.

Instead, the National Academy of Sciences panel tried to lay out some principles to guide further discussions. The development of any new regulations around genome-editing needs to be transparent and open, with ample public input. For instance: "Ongoing reassessment and public participation should precede and clinical trials of heritable germline editing." And: "Incorporate public participation into the human genome editing policy process about 'enhancement.'"

Even experts who are steeped in this topic have wildly different views of what's appropriate. Back in 2015, a group of scientists wrote a letter in Nature calling for a moratorium on all embryo editing, period. The authors, led by Edward Lanphier of the DNA editing company Sangamo Therapeutics, argued that the potential benefits were still too hazy right now and the risks were too great:

In our view, genome editing in human embryos using current technologies could have unpredictable effects on future generations. This makes it dangerous and ethically unacceptable. Such research could be exploited for non-therapeutic modifications.

The critics also worried that a backlash against embryo modification could end up stifling promising research around gene therapy (No. 2 on our list in the last section):

We are concerned that a public outcry about such an ethical breach could hinder a promising area of therapeutic development, namely making genetic changes that cannot be inherited.

In an interview with Science on Tuesday, the lead author of that essay, Lanphier, expressed disappointment with the new NAS report's cautious approval of embryo editing in some cases: "It changes the tone to an affirmative position in the absence of the broad public debate this report calls for."

By contrast, George Church, a geneticist at Harvard and one of the pioneers of CRISPR, has long argued that while the benefits of editing embryos seem small right now, they are compelling enough to expand research. Here's what he told Stat in 2015:

We need only one compelling argument to initiate a new social norm - even when the market is small (as for orphan drugs). For germline modification, we have at least three compelling cases: 1) mitochondrial diseases; 2) families in which post-natal remedies are inadequate and both parents are fully afflicted (20 percent of the world's marriages involve close relatives); and 3) scenarios in which treating (and possibly pre-screening) single germ cells is safer than treating millions of somatic cells, since each cell adds to the collective risk of developing cancer.

In that same piece, NIH director Francis Collins is much more worried about the potentially risky side effects of human germline editing; you should read their entire exchange.

This new report is hardly going to be the last word on this debate, but the NAS tends to be influential in guiding US government policy, and it's nudged the discussion significantly in the direction of allowing designer babies - even in limited cases.

Further reading

A simple guide to CRISPR, one of the biggest science stories of the decade

While designer babies get all the attention, there are tons of cool things CRISPR can do that have nothing to do with editing humans. Here's a list of a few.

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This new report on the future of genetically engineered humans is essential reading

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Biotechnology has advanced so rapidly over the past few years that scientists can now edit the genomes of plants and animals with ever-increasing precision. Using new techniques like CRISPR/Cas9, researchers have already shown they can alter genes to create hornless cattle or mushrooms that don't brown easily.

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A CNET article about CRISPR

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We are in the midst of a gene-editing revolution.

For four decades, scientists have tinkered with our genes. Since the 1970s, they've experimentally switched them on and off, uncovering their functions; mapped their location within our genome; and even inserted or deleted them in animals, plants and human beings.

And in November 2018, a Chinese scientist claimed to have created the world's first genetically modified human beings.

Though scientists have made great inroads into understanding human genetics, editing our genes has remained a complex process requiring imprecise, expensive technology, years of expertise and just a little luck, too.

In 2012, a pair of scientists developed a new tool to modify genes, reshaping the entire field of gene-editing forever: CRISPR. Often described as "a pair of molecular scissors," CRISPR is widely considered the most precise, most cost-effective and quickest way to edit genes. Its potential applications are far-reaching, affecting conservation, agriculture, drug development and how we might fight genetic diseases. It could even alter the entire gene pool of a species.

The field of CRISPR research is still remarkably young, yet we've already seen how it might be used to fight HIV infection, combat invasive species and destroy antibiotic-resistant bacteria. Many unknowns remain, however, including how CRISPR might damage DNA, leading to pathologies such as cancer.

Such a monumental leap in genetic engineering is full of complexities that ask big, often philosophical questions about science, ethics, how we conduct research and the future of humanity itself. With the confirmation that two human embryos were modified using CRISPR and carried to term, those questions have come sharply into focus. The future of gene-editing seemingly arrived overnight.

But what exactly is CRISPR and what are the outstanding concerns about such a powerful tool?

Let's break it all down.

What is CRISPR?

Few predicted how important CRISPR would become for gene editing upon its discovery 30 years ago.

As early as 1987, researchers at Osaka University studying the function of Escherichia coli genes first noticed a set of short, repeated DNA sequences, but they didn't understand the significance.

Six years later, another microbiologist, Francisco Mojica, noted the sequences in a different single-celled organism,Haloferax mediterranei. The sequences kept appearing in other microbes and in 2002, the unusual DNA structures were given a name: Clustered regularly interspaced short palindromic repeats.

CRISPR.

Studying the sequences more intensely revealed that CRISPR forms an integral part of the "immune system" in bacteria, allowing them to fight off invading viruses. When a virus enters the bacteria, it fights back by cutting up the virus' DNA. This kills the virus and the bacteria stores some of the leftover DNA.

The leftover DNA is like a fingerprint, stored in the CRISPR database. If invaded again, the bacteria produce an enzyme called Cas9 that acts like a fingerprint scanner. Cas9 uses the CRISPR database to match the stored fingerprints with those of the new invader. If it can find a match, Cas9 is able to chop up the invading DNA.

Eric Mack

How is CRISPR used to edit genes?

Nature often provides great templates for technological advances. For instance, the nose of a Japanese bullet train is modeled on the kingfisher's beak because the latter is expertly "designed" by evolution to minimize noise as the bird dives into a stream to catch fish.

In a similar way, CRISPR/Cas9's ability to efficiently locate specific genetic sequences, and cut them, inspired a team of scientists to ask whether that ability could be mimicked for other purposes.

The answer would change gene editing forever.

In 2012, pioneering scientists Jennifer Doudna, from UC Berkeley, and Emmanuelle Charpentier, at Umea University Sweden, showed CRISPR could be hijacked and modified. Essentially, they'd turned CRISPR from a bacterial defense mechanism into a DNA-seeking missile strapped to a pair of molecular scissors. Their modified CRISPR system worked marvelously well, finding and cutting any gene they chose.

Several research groups followed up on the original work, showing that the process was possible in yeast and cultured mouse and human cells.

The floodgates opened, and CRISPR research, which had long been the domain of molecular microbiologists, skyrocketed. The number of articles referencing CRISPR in preeminent research journal Naturehasincreased by over 6,000 percent between 2012 and 2018.

While other gene-editing tools are still in use, CRISPR provides a gigantic leap because of its precision and reliability. It's really good at finding genes and making accurate cuts. That allows genes to be cut out with ease, but it also provides an opportunity to paste new genes into the gap. Previous gene-editing tools could do this, too, but not with the ease that CRISPR can.

Another huge advantage CRISPR has over alternative gene-editing techniques is its expense. While previous techniques might cost a laboratory upward of $500 to edit a single gene, a CRISPR kit can do the same thing for under $100.

What can CRISPR do?

The CRISPR/Cas9 system has been adapted to enable gene editing in organisms including yeast, fungi, rice, tobacco, zebrafish, mice, dogs, rabbits, frogs, monkeys, mosquitoes and, of course, humans -- so its potential applications are enormous.

For research scientists, CRISPR is a tool that provides better, faster tinkering with genes, allowing them to create models of disease in human cell lines and mouse models with much higher proficiency. With better models of say, cancer, researchers are able to fully understand the pathology and how it develops, and that could lead to improved treatment options.

One particular leap in cancer therapy options is the genetic modification of T cells, a type of white blood cell that's critical for the human immune system. A Chinese clinical trial extracted T cells from patients, used CRISPR to delete a gene that usually acts as an immune system brake, and then reintroduced them into the patients in an effort to combat lung cancer. And that's just one of the many trials underway using CRISPR edited cells to fight particular types of cancer.

Beyond cancer, CRISPR has the potential to treat diseases caused by a mutation in a single gene, such as sickle cell anemia or Duchenne muscular dystrophy. Correcting a defective gene is known as gene therapy, and CRISPR is potentially the most powerful way to perform it. Using mouse models, researchers have demonstrated the efficacy of such treatments but human gene therapies using CRISPR remain untested.

Then there are CRISPR gene drives, which use CRISPR to guarantee a genetic trait will be passed from parent to offspring -- essentially rewriting the rules of inheritance. Guaranteeing certain genes will spread through a population provides an unprecedented opportunity to tackle mosquito-borne diseases such as malaria, enabling scientists to create infertile mosquitoes in the lab and release them in the wild to crash the population -- or even render a species extinct.

And CRISPR's potential benefits don't end there. The tool opens up new ways of creating antimicrobials to combat rising levels of antibiotic resistance, targeted manipulation of agricultural crops such as wheat to make them hardier or more nutritious, and, potentially, the ability to design human beings, gene by gene.

CRISPR concerns

CRISPR may be the most precise way to cut DNA we've yet discovered, but it's not always perfect.

One of the chief barriers to getting CRISPR effectively working in humans is the risk of "off-target effects." When CRISPR is tasked with hunting down a gene, it sometimes finds genes that look very similar to its target and cuts them, too.

An unintended cut may cause mutations in other genes, leading to pathologies such as cancer, or it may have no effect at all -- but with safety a major concern, scientists will need to ensure CRISPR acts only on the gene it's intended to impact. This work has already begun, and several teams of researchers have tinkered with CRISPR/Cas9 to increase its specificity.

To date, CRISPR work in humans has been confined to cells that don't pass on their genome to the next generation. But gene editing can also be used to edit embryos and thus, change the human gene pool. In 2015, an expert panel of CRISPR scientists suggested that such editing -- known as germline editing -- would be irresponsible until consensus can be reached on safety, efficacy, regulation and social concerns.

Still, research into germline editing has been occurring for several years. In 2017, scientists in the UK edited human embryos for the first time, and researchers in the US used CRISPR to correct a defective gene that causes heart disease. The ability to edit embryos begins to raise ethical concerns about so-called designer babies, wherein scientists may select beneficial genes to increase physical fitness, intelligence or muscle strength, creeping into the controversial waters of eugenics.

That particular future is likely a long way off -- but the era of editing the human genome has already begun.

Editing humans

On Nov. 25, 2018, Chinese scientist Jiankui He said he had created the world's first CRISPR babies. By using CRISPR, He was able to delete a gene known as CCR5. The modified embryos resulted in the birth of twin girls, known by the pseudonyms Lulu and Nana.

The scientific community widely condemned the research, criticizing He's lack of transparency and asking whether there was an unmet medical need for the two girls to receive such a modification. In the wake of the research, several high-profile researchers involved with CRISPR's creation even suggested a global moratorium on using the tool for germline editing.

Few would argue that He's work highlights a need for stricter regulatory controls and effective oversight of clinical trials in which embryos are edited. While He maintains his own experiment was concerned with improving the health of the twin girls by making them HIV-resistant, the experiment was deemed reckless and ethically wrong and the potential consequences overlooked. In January 2019, the Chinese government said that He acted both unlawfully and unethically and would face charges. He was later dismissed by his university.

The most recent International Summit for Human Genome Editing, in November 2018, concluded, as it did in 2015, "the scientific understanding and technical requirements for clinical practice remain too uncertain and the risks too great to permit clinical trials of germline editing at the time."

He's work, which remains unpublished, heralds the first clinical trial and birth of genetically modified human beings -- which means, whether it was the intention or not, a new era for CRISPR has begun.

We've already seen CRISPR transform the entire field of molecular biology -- and that effect has rippled across the biological and medical fields at lightning speed. In only six years, CRISPR went from an evolutionary adaptation in bacteria to a gene-editing tool that, potentially, created the very first genetically modified human beings.

As the revolution surges forward, the greatest challenges will lie in oversight and regulation of the technology, the technical hurdles that science must overcome to ensure it is precise and safe, and the larger societal concerns of tinkering with the stuff that makes us

And the Nobel Prize for medicine goes to...: Two researchers for their cancer breakthrough.

Changes in consumer health tech: CES 2018 gets serious about health, wellness and medical tech

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CRISPR explained: The revolutionary tool that's transforming genetic engineering

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We are in the midst of a gene-editing revolution. For four decades, scientists have tinkered with our genes. Since the 1970s, they've experimentally switched them on and off, uncovering their functions; mapped their location within our genome; and even inserted or deleted them in animals, plants and human beings.

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A Wired magazine article about genetic engineering

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The distant future of designer babies might not seem so distant after all. The last year has been full of news about genetic engineering-much of it driven by the the cut-and-paste technique called Crispr. And at the top of the list: news that Crispr could modify human embryos, correcting a relatively common, often deadly mutation.

The researcher who spearheaded that work in the US, a controversial cell biologist named Shoukhrat Mitalipov, said not only that his team had used Crispr to correct a mutation in a newly fertilized embryo, but that they'd done it via a mechanism that was, if not novel, at least unusual. The response from the scientific community was immediate and negative. They just kinda didn't buy it. So Wednesday, in the journal Nature-where Mitalipov published the initial work-two groups of researchers published pointed, acronym- and infographic-filled critiques of Mitalipov's 2017 paper, and Mitalipov attempted to respond. Because the ethics don't matter-well, not yet-if the science doesn't actually work.

You know how babies are made, right? Well, Mitalipov's team didn't do it that way. Using existing human embryos for scientific research is mostly a no-no in the US, so the scientists took normal human eggs and fertilized them with sperm containing a mutant version of a gene called MYBPC3. That version underlies a disease called hypertrophic cardiomyopathy, the most common cause of sudden death in young athletes. People with two copies of mutant MYBPC3-one from Mom and one from Dad, or homologous for the allele, in the language of genetics-rarely survive childhood. People with just one copy-heterozygous-often have heart problems as they get older.

To try to correct the mutation, Mitalipov's team used Crispr to cut the mutant gene from the paternal chromosomes and then insert a synthetic, corrected version. But that second step didn't happen. Instead, according to Mitalipov's analysis, the cell copied the wild type gene from the maternal chromosomes and inserted that instead. The result: embryos with two wild type alleles. It's called "homology-dependent repair" or "inter-homolog homologous repair."

"Some of these authors had been studying DNA repair, and somehow they missed this elephant in the room," says Mitalipov, the director of the Center for Embryonic Cell and Gene Therapy at Oregon Health and Science University. "We're pointing to a huge gap in knowledge about how genes repair. We're not sure if it happens in somatic lineages, but in embryonic lineages, we've now proved it."

Embryologists and cell biologists didn't think they'd missed an elephant. They didn't think there was one. "We thought there was an alternative interpretation," says Paul Thomas, director of SA Genome Editing at the South Australian Health and Medical Research Institute and a lead author of one of the critique articles. Thomas' work has shown that in mice, Crispr tends to cut big chunks of DNA out of the genome, so-called large deletions. He suspects that's what happened in the Mitalipov embryos, too-they were missing large-deletion failures. "If there's a large deletion created on the chromosome, you need to look specifically for that event," Thomas says. "And if you use the assay they used, a pretty standard assay, that won't detect it."

It'd be like trying to figure out how many kinds of bagels a bakery makes by counting what's on the shelf at the end of the day. Your stats would say the bakery mostly makes blueberry, but that's because the good flavors like poppy seed, garlic, salt, and plain were invisible-bought before you got there. Your count would overestimate blueberry output as a proportion of overall bagelry.

Could this just be a problem of mice and men? Sure. "It's certainly the case that more and more people are seeing large deletions in mouse embryos. What's not clear is whether large deletions are occurring in human embryos, because really we only have this study and a handful of others," Thomas says.

So Mitalipov's group went back to the lab. They took their old samples and reran the assay, a technique called polymerase chain reaction that makes large enough volumes of DNA to sequence and analyze. This time, they looked at a longer stretch of the chromosome. "We did assays with large-scale PCR, up to 10,000 base pairs, and we still didn't see any deletions," Mitalipov says. He didn't expect to find any. His group's first paper reported a success rate-which is to say, a rate of fixing the mutation-of around 70 percent. Mitalipov says it's hard to believe that he'd have Crispr-induced large deletions in 70 percent of his embryos. That'd render the technique broadly unusable, he says.

Case not closed, though. "We're quite surprised they don't see any evidence of deletions in any of the samples in their response paper," Thomas says. "We don't think they've fully excluded the possibility." Fatwa Adikusuma, one of Thomas' coauthors, suggests a more precise assay like qPCR (which looks at the amount of DNA quantitatively-hence the Q) would work. Mitalipov didn't try that.

Other teams had other questions. For example, a group led by Dieter Egli of Columbia University and Maria Jasin of Memorial Sloan Kettering Cancer Center (and including the outspoken Harvard biotechnologist George Church) wondered how the Crispr complex could've gotten ahold of the maternal wild-type gene, since the mom-contribution and the dad-contribution are separate for the early parts of cell division. Mitalipov says the clusters of parental DNA, contained in envelopes called pronuclei, come into contact with plenty of time for the repair process to work. "If that's correct, then it's puzzling that they don't report more mosaicism in those embryos," says Paul Knoepfler, a cell biologist at UC Davis. "Mosaicism" is when a single organism has different genomes in different cells. "Crispr acting so late, such as at the two-cell embryo stage, would likely cause variable genetic outcomes," Knoepfler says-and that could make for less healthy embryos later on.

So is it possible that Mitalipov got it right? "As presented, the new data is consistent with gene correction," Jasin writes in an email. But, she says, Mitalipov's own response shows how tough this kind of research is. One of his embryos showed "allele dropout," when his team couldn't detect alleles from both parents. "It is uncertain whether gene correction by inter-homolog recombination occurred in all of the embryos, some of the embryos, or, in the most extreme case, none of the embryos," Jasin adds.

Everyone, including Mitalipov, says it'll take more research to be sure. That's fine with him; he understands that people have plenty of concerns about what he says he did. If his method really works, it only works in embryos with one wild-type copy of a gene, for one thing-there has to be a wild-type version of the gene for the cell to copy. But more than that, it takes time and work for new ideas to penetrate a field. "There are dogmas, particularly in biology," Mitalipov says. "And we just bumped in with our result, saying this is an unknown but strong repair pathway in human embryos."

It'll certainly take time for that "dogma" to make way for this approach. "Mitalipov's team has strengthened their case somewhat," Knoepfler says. "Maybe this is pointing us in the direction of understanding fundamentally new mechanisms in early human embryos, but it's also possible that a year from now we'll view this entirely differently." Either way, for something to get to the clinic, it'll have to perform better than 70 percent. That means it's time for more work in the lab.

More Great WIRED Stories

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Scientists Take a Harder Look at Genetic Engineering of Human Embryos

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The distant future of designer babies might not seem so distant after all. The last year has been full of news about genetic engineering-much of it driven by the the cut-and-paste technique called Crispr. And at the top of the list: news that Crispr could modify human embryos, correcting a relatively common, often deadly mutation.

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An article in the journal Nature

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Much of what we currently know about the ramifications of genetic self-knowledge comes from testing for diseases. Once disease genes were identified, it became much easier to make a molecular or cytogenetic diagnosis for many genetic conditions. Diagnostic testing supplies the technical ability to test presymptomatic, at-risk individuals and/or carriers to determine whether they will develop a specific condition. This sort of testing is a particularly attractive choice for individuals who are at risk for diseases that have available preventative measures or treatments, as well as people who might carry genes that have significant reproductive recurrence risks. Indeed, thanks to advances in single-cell diagnostics and fertilization technology, embryos can now be created in vitro; then, only those embryos that are not affected by a specific genetic illness can be selected and implanted in a woman's uterus. This process is referred to as preimplantation genetic diagnosis.

For adult-onset conditions, ethical concerns have been raised regarding whether genetic testing should be performed if there is no cure for the disease in question. Many people wonder whether positive diagnosis of an impending untreatable disease will harm the at-risk individual by creating undue stress and anxiety. Interestingly, social science research has demonstrated that the answer to this question is both yes and no. It seems that if genetic testing shows that an individual is a carrier for a recessive disease, such as Tay-Sachs disease or sickle-cell anemia, this knowledge may have a negative impact on the individual's well-being, at least in the short term (Marteau et al., 1992; Woolridge & Murray, 1988). On the other hand, if predictive testing for an adult-onset genetic disorder such as Huntington's disease reveals that an at-risk individual will develop the disorder later in life, most patients report less preoccupation with the disease and a relief from the anxiety of the unknown (Taylor & Myers, 1997). For many people who choose to have predictive testing, gaining a locus of control by having a definitive answer is helpful. Some people are grateful for the opportunity to make life changes-for instance, traveling more, changing jobs, or retiring early-in anticipation of developing a debilitating condition later in their lives.

Of course, as genetic research advances, tests are continually being developed for traits and behaviors that are not related to disease. Most of these traits and behaviors are inherited as complex conditions, meaning that multiple genes and environmental, behavioral, or nutritional factors may contribute to the phenotype. Currently, available tests include those for eye color, handedness, addictive behavior, "nutritional" background, and athleticism. But does knowing whether one has the genetic background for these nondisease traits negatively affect one's self-concept or health perception? Studies are now beginning to address this question. For example, one group of scientists performed genetic testing for muscle traits on a group of volunteers enrolled in a resistance-training program (Gordon et al., 2005). These tests looked for single-nucleotide polymorphisms that would tell whether an individual had a genetic predisposition for muscle strength, size, and performance. The investigators found that if the individuals did not receive affirmative genetic information regarding muscle traits, they credited the positive effects of the exercise program to their own abilities. However, those study participants who did receive positive test results were more likely to view the beneficial changes as out of their control, attributing any such changes to their genetic makeup. Thus, a lack of genetic predisposition for muscle traits actually gave subjects a sense of empowerment.

The results of the aforementioned study may be surprising to many people, as one major concern associated with testing for nondisease traits is the fear that those people who do not possess the genes for a positive trait may develop a negative self-image and/or inferiority complex. Another matter bioethicists often consider is that people may discover that they carry some genes associated with physiological or behavioral traits that are frequently perceived as negative. Moreover, many critics fear that the prevalence of these traits in certain ethnic populations could lead to prejudice and other societal problems. Thus, rigorous social science research by individuals from diverse cultural backgrounds is crucial to understanding people's perceptions and establishing appropriate boundaries.

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genes and identity: human genetic engineering

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genetic engineering  eugenics  designer babies  genetic aristocracy

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Genes and Identity: Human Genetic Engineering

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Imagine having the option of custom making your body to possess the physical strength of Arnold Schwarzenegger or the endurance of Lance Armstrong. And what if you could choose to have your children look like Angelina Jolie or Brad Pitt, as well as have the intelligence of Albert Einstein?

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This site has links to several articles about genetic engineering.

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Researchers at Sun Yat-sen University in Guangzhou, China published a paper on April 18, 2015, detailing the first use of the "gene editing" technology CRISPR in human embryos. The news initiated a global media firestorm about the irresponsibility of attempting to create genetically modified humans.

The experiments were largely unsuccessful. But as gene editing tools are refined in labs around the world, they are expected to allow easier, cheaper and more accurate insertion or deletion of genes than ever before...

Genome editing is a way of making changes to specific parts of a genome. Scientists have been able to alter DNA...

Public and policy conversations about heritable human genome editing often leave the impression that rules governing it are few and...

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Human genetic modification (or "gene editing") can be used in two very different ways. Somatic genome editing changes the genes in a patient's cells to treat a medical condition. A few gene therapies are approaching clinical use but remain extraordinarily expensive.