Fertility paradox in male beauty quest

So the glands react by shutting down the production of two hormones – called FSH and LH – which are the key hormones that drive the production of sperm.

The researchers say there is a similar theme in men using medication to prevent male pattern baldness.

The drug finasteride changes the way testosterone is metabolised in the body and can limit hair loss, but side effects can include erectile dysfunction and a hit to fertility.

Prof Pacey told the BBC: “I would say more anabolic steroid users are likely to become sterile than you would think – 90% probably.

“Baldness is a bit more hit-and-miss, but sales are going through the roof and that makes it an increasingly common problem.”

‘Evolutionary dud’

The measure of success in evolutionary terms is passing on your genes (instructions in your DNA) to the next generation.

Dr Mossman said taking these vanity-based medications might make you more attractive but could turn you into “an evolutionary dud”.

It is not the equivalent of the extravagant peacock’s tail, which makes males more attractive to females and increases the chances of passing genes on to the next generation.

There are some examples in the natural world where an animal sacrifices their ability to breed.

Some bird species perform co-operative breeding in which individuals forego having their own offspring to help raise the descendants of close relatives.

But even this can make sense in evolutionary terms as half of your genes are shared with siblings so they are still being passed on, just indirectly.

Dr Mossman suspects “thinking you’re more appealing to the opposite sex, but killing your fertility” is probably unique to humans.

Prof Pacey told the BBC: “The irony is one thing, but I think the key message is for fertility patients.

“It keeps cropping up in clinics and the message is not getting out to young men that it’s a problem and a bit of info could save them a lot of heartache.”

Source: BBC