Many transgender or transsexual (TG/TS) people wish to change their birth certificates and other legal documents to reflect their new gender. Think of all the times you've needed to use your driver's license, state ID, birth certificate, or passport. What if the 'sex' on these documents didn't reflect your actual identity? Problems can, and definitely do, arise. 

So transpeople ask to change their documents. Seems pretty reasonable, no? 

Yet people born in Idaho, Ohio, South Carolina, and Tennessee can't change the sex on their birth certificates. As in, at all. On the other end of this spectrum is Indiana, which doesn't indicate sex at all on their birth certificates- Problem solved.

In most states, however, TG/TS people have to jump through hoop after hoop to change theirs. They have to present a letter from a surgeon stating they underwent gender confirmation surgery, which is usually only considered to be surgery on their genitals. This is problematic for several reasons:
First, not everyone wanting to change their gender wants surgery. Maybe they don't want the possibility of complications. Maybe they don't feel compelled to change their genitals. Maybe they don't feel the current options are adequate. 
Second, surgery is expensive and insurance almost never pays for any of it. 
Third, some surgeons will not write letters for people. 
Fourth, for some document changes (like a passport) the surgeon must be in the USA and many transpeople go to surgeons (like in Thailand or Serbia) for their surgeries. 

Then come the battles with the DMV, the Passport Agency, the State Court, Social Security... 
Vermont USED to be one of those states... but not anymore! Now someone can change their sex marker on documents by getting a letter from a doctor stating they have undergone surgery OR hormone therapy OR another treatment for the purpose of gender transition. While this still requires the person to go through the process of getting a letter from a supportive physician and then going to the appropriate agency for the change, it does open the doors to sex marker change to a lot more folks. Way to go Vermont! 

The exact language of the amendment is below: 
"An affidavit by a licensed physician who has treated or evaluated the individual stating that the individual has undergone surgical, hormonal, or other treatment appropriate for that individual for the purpose of gender transition shall constitute sufficient evidence for the court to issue an order that sexual reassignment has been completed."

Additionally, previously on birth certificates that were changed, the name and sex were shown as having been changed- not something you probably want a viewer (like a potential employer) to see. But this was also changed with the amendment, saying:
"The new certificate shall not show that a change in name or sex, or both, has been made. The original birth certificate, the probate court order, and any other records relating to the issuance of the new birth certificate shall be confidential and shall not be subject to public inspection"

A special shout-out to Rep. Bill Lippert (who first brought this up in the House),  VT Health Commissioner Dr. Harry Chen (who requested this specific amendment), and Gov. Peter Shumlin (who signed it into law).