Women's groups are accusing the Bush administration of putting politics before science in rejecting over-the-counter sales of morning-after birth control (search), even though regulators left open the possibility they will reconsider.

The Food and Drug Administration (search) cited concern about young teenagers' use of the pills in rejecting the move Thursday.

The decision overruled a recommendation from FDA's own scientific advisers, who had overwhelmingly called easier access to emergency contraception a safe way to prevent thousands of abortions.

A disappointedBarr Laboratories (search), maker of the Plan B emergency contraception brand, plans to rapidly seek nonprescription sales approval again — at least to people age 16 and older.

"It's a matter of weeks and months to deal with this objection," said Barr chief executive Bruce Downey, saying that means the FDA could reconsider the issue within a year. "Clearly ... the door's open, and we plan to go through it."

The FDA complained that Barr provided no evidence that teens under 16 could use the pills appropriately without a doctor's guidance. Warned in February of that concern, Barr offered a last-minute proposal to allow nonprescription sales to anyone 16 and older — and make drugstores check ages and demand a prescription from younger teens.

But the FDA said the company didn't provide necessary details on how such a program, never before tried, would work. It said, though, it would reconsider if Barr provided more details and teen data.

"Wide availability of safe and effective contraceptives is important to public health," FDA acting drug chief Dr. Steven Galson wrote the company. "We look forward to continuing to work with you if you decide to pursue either of these options."

The morning-after pill is a higher dose of regular hormonal contraception. Taken within 72 hours of unprotected intercourse, it can cut a woman's chances of pregnancy by up to 89 percent. But it can be hard to find a doctor to write a prescription in time, especially on weekends and holidays.

Contraceptive advocates and doctors' groups say easier access could reduce by half the nation's 3 million unintended pregnancies each year. In December, FDA's scientific panel agreed, voting 23-4 that nonprescription sales would be a safe and important way to prevent abortions.

Afterward, the FDA came under months of intense political pressure from conservatives who argued that unfettered access could encourage more teen sex.

Women's groups charged Thursday that the agency cracked.

"The decision blatantly disregards the overwhelming scientific evidence," said Kirsten Moore of the Reproductive Health Technologies Project. "The Bush administration has denied American women timely access to a safe, proven second chance to prevent pregnancy."

"The White House is putting its own political interests ahead of sound medical policies that have broad support," said a spokesman for Democratic presidential candidate John Kerry.

The FDA's move will "have a negative impact on the public health," said Dr. Alastair Wood of Vanderbilt University, one of FDA's scientific advisers who noted that many other countries allow nonprescription sales.

But conservatives welcomed the decision.

"The FDA is siding with our nation's teens and their health," said Rep. Dave Weldon, R-Fla., himself a doctor.

"The FDA is right to be cautious about having a potent drug that can harm women next to candy bars and toothpaste," said Wendy Wright of Concerned Women for America, a group that opposes abortion.

Within the FDA, the decision was mixed. An internal agency memo, obtained by The Associated Press, suggests medical reviewers backed nonprescription sales but were overruled by senior officials.

"Some staff have expressed the concern that this decision is based on non-medical implications of teen sexual behavior, or judgments about the propriety of this activity," said Galson's memo. "These issues are beyond the scope of our drug approval process, and I have not considered them in this decision."

Galson wrote that "despite the urgent need to prevent pregnancy" among 11- to 14-year-olds, Barr provided no data on how younger teens would use the nonprescription pills.

Studies on college campuses show a decline in pregnancy and abortion with wider availability of the morning-after pill.

To improve access, five states — California, Washington, Alaska, Hawaii and New Mexico — already allow women to buy morning-after pills from certain pharmacists without a prescription. The FDA's decision does not affect those programs.

If a woman already is pregnant, morning-after pills have no effect.