Beginning in October, U.S. scientists who want government money to fund their research will have to start using female animals and cells in their research.
The announcement from the U.S. National Institutes of Health (NIH)
, the biggest funder of medical research in this country, is seen as a major development because male specimens traditionally dominate drug research.
Curtis Meinert, at Johns Hopkins University's Bloomberg School of Public Health
in Baltimore, Maryland, is an expert in the design of clinical trials. He believes results from men apply to women, too.
"In general, things that work, work," Meinert said. "And so it's independent of male or female. So to some degree I expect it doesn't make much difference."
Not so, according to Phyllis Greenberger, president of the Society for Women's Health Research
"When researchers have looked at sex differences, they sometimes find that something works better in a man versus a woman or the other way around," she said. "So it's not just about women anymore. It's really understanding the mechanism of disease."
Lobbying efforts by women's health advocates led Congress to pass a law in the 1990s requiring federally-funded research to include more women in large clinical trials.
Before then, it was widely believed that what works in men works for women.
Janine Austin Clayton, an ophthalmologist by training who directs the Office of Research on Women's Health
at the National Institutes of Health, says participants in NIH-funded research now include an equal number of men and women.
The two genders respond differently to different drugs, says Clayton. For example, some medication can be harmful to women at the doses recommended for men.
"We want to understand that so that when I'm treating a patient any day ‒
my mother, your father ‒
I can design that treatment with that patient in mind, with sex-specific evidence behind it," she said.
Clayton adds that certain illnesses, such as heart disease and some eye conditions, manifest differently in women and men, which is why drugs and dosing need to be tailored for women.