Young male gym users are largely unaware of the risks of their lifestyle on their fertility, new research has found.
This includes the impact protein supplements, used by 79 per cent of respondents, which can contain high levels of oestrogen.
When questioned about their concern about fertility, more than half (52 per cent) of male participants said that they had thought about their fertility before.
However, only 14 per cent of men who took part had considered how gym routines or supplement use might impact on fertility.
Meanwhile there was a significant difference in responses about whether the benefits of gym routines and supplements were more important to them than fertility, with 38 per cent disagreeing and 28 per cent agreeing.
However, female participants were more aware of the impact of gym lifestyle on male fertility.
Dr Meurig Gallagher from the University of Birmingham and lead author of the study said: “Being healthy and having a healthy lifestyle is a good thing.
“In the context of male fertility, the concern is over the increasing use of protein supplements.
“The main concern is the high levels of the female hormone oestrogen that comes from both whey and soy protein supplements.
“Too much female hormone can cause problems with the amount and quality of sperm that a man can produce.
“Many protein supplements that can be bought have been found to be contaminated by anabolic steroids, which can cause reduced sperm count, shrunken testicles, and erectile dysfunction amongst other things.”
Infertility is a problem of increasing concern, affecting 1 in 6 people worldwide according to the World Health Organization.
Globally, there is limited understanding of the fact that men contribute to half of all fertility cases.
While many of the men surveyed were aware of the risks of anabolic steroid-use, new were aware that protein supplements carried potential risks.
Professor Jackson Kirkman-Brown from the University of Birmingham and author of the paper said:
“We found that men are genuinely curious about their fertility when prompted, but that they don’t think about it on their own – likely because societally people still think of fertility as a ‘female issue’ and (incorrectly) believe that men’s fertility doesn’t change throughout their lifetimes.”