Study: Men with smaller testes more likely to be involved father

Photo by Flickr user Susan Sermoneta

Men with smaller testes are more likely to be involved in raising their toddlers, according to a study published in the Proceedings of the National Academy of Sciences Monday. Researchers at Emory University studied 70 fathers with children ages one to two years old. They found men with smaller testicular volume were more likely to be involved in hands-on parenting: changing diapers, feeding children, bathing a child and caring for sick children.

Emory anthropologist James Rilling, whose lab conducted the research, said in a press release: “We’re assuming that testes size drives how involved the fathers are, but it could also be that when men become more involved as caregivers, their testes shrink. Environmental influences can change biology.”

H/T Rebecca Jacobson