City health officials Tuesday backed off a plan that would have allowed New Yorkers to switch the sex on their birth certificates without first undergoing sex-change surgery.

Health Commissioner Thomas Frieden said the issue needed further study, in part to guarantee it would not conflict with federal rules now being developed.

Like most other cities and states, New York has long allowed people who have undergone sex-change surgery to get a new birth certificate reflecting the change.

The city's Department of Health and Mental Hygiene had proposed in September that the policy be liberalized further to include people who had taken other steps short of surgery to irrevocably alter their gender identity.

The new policy, for example, would have allowed birth record changes for people taking hormones to alter their appearance.

While it delayed making that change, the Board of Health went ahead with a related policy revision that for the first time will allow people who have undergone sex-change surgery to list their new sex on their birth documents. Previously, the city had simply issued a new birth certificate that removed any reference to gender.