Argentina set the new standard for changes in gender markers on identity documents for trans people:
“The fact that there are no medical requirements at all — no surgery, no hormone treatment and no diagnosis — is a real game changer and completely unique in the world. It is light years ahead of the vast majority of countries, including the U.S., and significantly ahead of even the most advanced countries,” said Eisfeld, who researched the laws of the 47 countries for the Council of Europe’s human rights commission.
In the US, you can get your passport changed with a letter from a doctor but no genital surgery is required, at least. The problems arise in the different ruling of the different states, so in Texas, for insance, a trans woman is always legally male, but she can legally marry her (cis) girlfriend there. Not quite how they expected the law against transness and against same sex marriage to play out, but there you go.