Scientists believe they have uncovered an evolutionary paradox where men damage their ability to have children during efforts to make themselves look more attractive to potential partners.
Taking steroids to get a buff physique or taking pills to keep a full head of hair can damage fertility. It has been named the Mossman-Pacey paradox after the scientists who first described it. They say it causes a lot of heartache in couples struggling to conceive.
Jim Mossman is a research associate in evolutionary biology at Brown University in Providence, Rhode Island. Newsday's Shaimaa Khalil asked him how he first became aware of the paradox.
(Photo: Bodybuilder performs during a championship. Credit: Getty Images)