WASHINGTON — Fifty years after the pill, another birth control revolution may be on the horizon: free contraception for women in the U.S., thanks to the new health care law.

That could start a shift toward more reliable — and expensive — forms of birth control that are gaining acceptance in other developed countries.

But first, look for a fight over social mores. A panel of experts advising the government meets in November to begin considering what kind of preventive care for women should be covered at no cost to the patient, as required under President Barack Obama's overhaul. Sen. Barbara Mikulski, D-Md., author of the women's health amendment, says the clear intent was to include family planning. But is birth control preventive medicine?

Conflicting answers frame what could be the next clash over moral values and a health law that passed only after a difficult compromise restricting the use of public money for abortions.

For many medical and public health experts, there's no debate.

"There is clear and incontrovertible evidence that family planning saves lives and improves health," said obstetrician-gynecologist Dr. David Grimes, an international family planning expert who teaches medicine at the University of North Carolina. "Contraception rivals immunization in dollars saved for every dollar invested. Spacing out children allows for optimal pregnancies and optimal child rearing. Contraception is a prototype of preventive medicine."

But U.S. Catholic bishops say pregnancy is a healthy condition, not an illness. In comments filed with the Department of Health and Human Services, the bishops say they oppose any requirement to cover contraceptives or sterilization as preventive care.