The city wants to make it easier for transgender New Yorkers to switch the sex listed on their birth certificate even without undergoing sex-change surgery, putting the city at the forefront of efforts to redefine gender.

Under present city rules, only people who can show proof of surgery qualify for getting a revised birth certificate. Even then, the only change made is the elimination of any reference to gender on the document.

The new plan, unveiled in September, would let birth records reflect the new gender. It would also allow changes for people who hadn't had genital surgery, but could show substantial proof that they have undertaken other steps to irrevocably alter their gender-identity — like undergoing hormone therapy.

The policy change is one that advocates for New York's sizable transgender community have requested for years, but which has taken on greater significance in a post-Sept. 11 world of increased security.

New Yorkers need to show picture ID to enter office towers, air terminals, public monuments and all sorts of government buildings. They need them to apply for a job too, or buy beer at a neighborhood deli.

The trouble comes when someone inspects those documents, and notices that a person's listed gender doesn't appear to match the way they look and dress.

"That can be a very dangerous situation for a transgender person," said Cole Thaler, transgender rights attorney for the national legal aid group Lambda Legal.

Thaler said having a birth certificate with a gender that matches a person's appearance will ease the way to getting other government records, including passports, drivers' licenses and Social Security records.

Lorna Thorpe, Deputy Commissioner of New York's Department of Health and Mental Hygiene, called the current system "outdated."

"A lot of transgender persons use different techniques to switch genders," she said. Some try hormones. A smaller number undergo surgery — in part because not everyone is medically capable of undergoing the procedure.

All but three states now allow people who have had a sex change to get a new birth certificate and New York City has done so since 1971. The city now issues about a dozen of the revised birth certificates a year.

Of the states that allow similar changes of birth certificates, almost all currently require proof of a gender-reassignment surgery.

Tennessee has a law expressly prohibiting a change of gender on a birth certificate. Ohio and Idaho also won't allow the change because of court rulings or as a matter of administrative policy.