But tests developed in the past decade make it much easier for scientists conducting clinical studies to control for women s cycles, Vandenbergh said. The IOM committee recommended some changes in the way clinical studies are done. Our committee does not recommend that all clinical studies include both men and women. If you re studying the effect of a drug on prostate cancer, it doesn t make much sense to put women into the study. On the other hand, if you re studying a drug for breast cancer, it might make sense to put men in some of the studies.
Men do have mammary tissue, and they, at a very low rate, get breast cancer.
By including men in a study of breast cancer, you might learn something about women. Research has shown that animals sexual behavior, anatomy and physiology are influenced by the hormones they encounter in the womb. Litter-born animals such as rodents and pigs are exposed to sex hormones in utero from other fetuses surrounding them, said Vandenbergh. Research has shown that in utero placement and the consequent exposure to male or female hormones have a lifetime effect on animals, although those effects vary greatly between species. Male mice prefer to mate with 2F female mice, and 2M female mice are more aggressive toward other females and to intruders than 2F females.