Scientists have warned that men are harming their fertility out of vanity, having been inspired by image-obsessed programmes such as Love Island.
Millions of people have turned to anabolic steroids to bulk up in an attempt to make themselves more attractive. But the drugs, which mimic the effects of testosterone in the body, can stop men producing any sperm, making them completely infertile - with the effects potentially lasting for longer than a year.
A hair loss drug called finasteride - which claims to reverse baldness - may have a similar effect on men’s fertility.
It has been described as a “fertility paradox” by British experts, who say some men may be trying to look better to attract women because, on an unconscious biological level, they want to impregnate them. But the result of the drugs could be that some men end up unable to do so.