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Balance of Males and Females

The number of male cells, tissues, and animals used in biomedical research outstrip the number of female ones used — by some 5.5 to 1 in neuroscience, notes Bethany Brookshire at Scicurious.

The US National Institutes of Health announced a policy change last May to try to fix that imbalance. The agency is beginning by requiring grantees to report the sex of the cells, tissues, and animals used in their studies.

As Brookshire reports, some researchers are happy with the new requirements while others say it is not funded well enough to work.

By focusing primarily on male cells, tissues, and animals, researchers maybe missing effects specific to females. For instance, dosage for the sleeping pill Ambien (zolpidem) for women had to be halved after it was discovered that they metabolized the drug more slowly and should take a smaller dose than men — an effect that might have been caught earlier had there been a balance of males and females in the clinical studies, Brookshire adds.

"Including females will require many labs to think more broadly about their approach, so as to include females in a cost-effective way," Jill Becker, a behavioral neuroscientist at the University of Michigan tells her. "These changes will be good for science in the long run."

However, others are worried about the added variables and added cost that will arise when folding another sex into an experimental design. The National Institute of Child Health and Development's Douglas Fields tells Brookshire that "the current approach hasn't given enough thought to the realities and practicalities" of such projects.

"I share the goals of the current approach, but my concern is that it will fail and cause a backlash among the public and undermine the effort," he adds.