WASHINGTON  Seventeen-year-olds will soon be allowed to buy morning-after contraceptive pills without a doctor’s prescription after federal drug regulators complied with a judge’s order and lowered the age limit by a year.

The decision on Wednesday by the Food and Drug Administration, which overturns one of the most controversial health rulings of the Bush administration, was scorned by abortion opponents and hailed by their abortion rights counterparts.

The long-running controversy involving Plan B has had more of a political impact than a public health one. The drug consists of two pills that can prevent conception if taken within 72 hours of sexual intercourse, and is not related to RU-486, the abortion pill. Since 2006, when Plan B became widely available to women 18 and over without a prescription, it has had no measurable effect on the nation’s abortion or teenage pregnancy rates.

Like their older counterparts, 17-year-old women will now be able to go to almost any pharmacy, clinic or hospital and, after showing proof of age, buy Plan B without a prescription. Men 17 and older may also buy Plan B for a partner.