Already under criticism for drug safety lapses, the FDA is now being drawn into a polarizing debate about reproductive choice and sexual mores.

Susan F. Wood, a biologist and veteran of 15 years in professional positions on Capitol Hill and in two administrations, took the unusual step of publicly announcing her resignation in an email to friends and colleagues that was distributed to the media by a policy group that favors reproductive choice.

"I can no longer serve ... when scientific and clinical evidence, fully evaluated and recommended for approval by the professional staff here, has been overruled," wrote Wood, 46, who has been at the agency nearly five years and held the title of assistant commissioner.

Polarizing Debate

FDA Commissioner Lester M. Crawford had announced Friday that even though the drug is safe, proposed restrictions on teenage girls' access to it have raised legal issues that must be examined in a process that could take months, or longer.

The FDA had earlier promised a decision by Sept. 1.

Wood's resignation brought calls from prominent Democratic lawmakers for hearings into the agency's handling of the issue. Already under criticism for drug safety lapses, the FDA is now being drawn into a polarizing debate about reproductive choice and sexual mores.

Proponents of the drug, marketed as Plan B, say making it more easily available will prevent unwanted pregnancies and reduce the number of abortions.

Opponents, including social conservatives in the Bush administration's political base, say it will encourage promiscuity, and they liken it to an abortion drug -- a position counter to the FDA's.

An FDA fact sheet about Plan B says it "works like other birth control pills to prevent pregnancy."