Men are damaging their chances of having children by going to the gym ‘to look wonderful and attract women’, experts have warned.
Scientists have said drugs used for muscle growth and anti-baldness pills can have side effects including erectile dysfunction and infertility.
The ironic effect has been labelled the Mossman-Pacey paradox after the scientists who first described it, noticing more buff men needing fertility tests.
Men are damaging their ability to have children by going to the gym ‘to look wonderful and attract women’: Experts warn about misuse of steroids and anti-baldness pills. Stock photo
Professor Allan Pacey, from the University of Sheffield, told the BBC: ‘Isn’t it ironic that men go to the gym to look wonderful, for the most part to attract women, and inadvertently decrease their fertility.’
Dr James Mossman, at Brown University Rhode Island, said: ‘They [some men] are trying to look really big, to look like the pinnacles of evolution.
‘But they are making themselves very unfit in an evolutionary sense, because without exception they had no sperm in their ejaculation at all.’
Dr Mossman was at Sheffield University studying for his doctorate when he noticed a lot of the men coming in to have their fertility tested were ‘huge’.
He then made the connection between poor fertility and the use of anabolic steroids, which are used to increase muscle mass and performance in the gym.
Anabolic-androgenic steroids (AAS), a type of image and performance-enhancing drug (IPEDs), are synthetically produced versions of the naturally occurring male sex hormone testosterone.
HOW DO STEROIDS HARM FERTILITY?
Anabolic steroids (also called anabolic-androgenic steroids) are drugs that are used to build muscle mass, improve performance or decrease body fat.
Whether AAS are injected or taken orally they work by mimicking testosterone.
When they enter the blood stream they attach to specific receptors at cell level. This allows them to enter the nucleus of the cell, which in turn helps the cell to create and retain more protein.
This process is called protein synthesis. It is this construction of new proteins that is associated with increased muscle size and strength.
Anabolic steroids harm male fertility by interfering with the hormone signals that are needed to produce sperm.
They fool the brain’s pituitary gland into thinking the testes are working too hard, and so the glands react by stopping the production of two hormones – called FSH and LH.
If used for long enough and in high enough doses, the damage to male fertility can become permanent. In some case, it may take up to a year for sperm production to return to normal having stopped the anabolic steroids.
However, they can block the production of testosterone in the testicles themselves, which is crucial for sperm production.
The effect can be reversed once the man stops using steroids in three months to a year. But if used for a long time in high doses, it can damage fertility permanently.
Professor Pacey, former chairman of the British Fertility Society, estimates that 90 per cent of anabolic steroid uses become sterile.
Anti-baldness pills are not as much of a concern, he said, however they are rising starkly in sales.
The drug finasteride, which is prescription only in the UK, lists sexual dysfunction as a ‘very common’ side effect, which includes a lower sex drive and the inability to get an erection.
It limits hair loss by changing the way testosterone is metabolised in the body, stopping it from being converted into dihydrotestosterone, a male androgen that’s been linked to balding.
In a study conducted by The George Washington University, published in JAMA Dermatology in 2014, roughly five per cent of men taking the medication experienced a decline in sperm count.
Dr Mossman believes humans are the only animals that sacrifice their fertility success in the hopes of attracting the opposite sex.
The two experts warned that men may be unclear on the potentially life-changing side effects of their vanity.
Professor Pacey said: ‘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.’
Drug charity FRANK warns users of IPEDS may become hooked on the way the drugs make them look and feel. The NHS warns they are addictive.
People of all ages have been known to misuse the class C drug, which are the only drug in the UK to have seen a staggering increasing of use.
An extra 19,000 young people had taken the drug in the year 2016-2017, official data showed.