Sexual orientation describes a person's enduring physical, romantic, and/or emotional attraction to another person (for example: straight, gay, lesbian, bisexual).

1932 – Magnus Hirschfeld performs the first ‘documented’ Sexual Reassignment Surgery (SRS) on Dora-R.

1949 – Harry Benjamin begins to treat transgender individuals in San Francisco with hormones.

1951 – 15th May: Robert Cowell becomes Roberta Cowell, the United Kingdom’s first fully surgically altered MTF transsexual. The surgery is performed by Sir Harold Gillies.

1966 – August: Compton’s Cafeteria Riots in San Francisco, the first recorded Trans riot in American history. The riot marks a turning point in the local LGBT movement as a network of transgender social, psychological, and medical support services is established.

1993 – Minnesota passes the first law in the US which prohibits discrimination against transgendered people. The Minnesota statute establishes protections for transgendered people under the rubric of sexual orientation.
https://www.theproudtrust.org/resources/trans-resources/trans-history/

Meanwhile, there are zero openly transgender Americans serving in Congress. At least 51 transgender people unsuccessfully ran for state, local and federal office last year, according to data collected by Logan Casey, a political scientist who now works with the Movement Advancement Project. Nine ran for Congress, but none emerged victorious or even won a major-party nomination.

Such political futility for transgender Americans specifically comes at a time when gay, lesbian and bisexual political candidates are winning some of the nation’s highest offices and even running for president in 2020.

https://publicintegrity.org/politics/elections/transgender-political-candidates-are-increasingly-common-the-money-backing-them-is-not/