For decades, male sperm counts have been plummeting. Now, doctors are warning increasing numbers of boys are being born with genital disorders.
Many boys’ testicles fail to descend, while others are born with the opening of their urethra, the tube out of which urine flows, is at the base of their penis, meaning they have to sit down to go to the loo.
Some experts blame gender-bending chemicals in the environment, commonly found in the plastic used in containers and our homes.
It is said they inhibit male sex hormones in the womb, which can lead to defects in a developing male foetus.
Others say the problem is linked to lifestyle factors – that eating more fat means we produce more of the female hormone oestrogen – which again, will affect how a baby in the womb grows.
Some chalk men’s falling sperm counts down to men’s bulging waistlines – as fat cells naturally produce more oestrogen which can affect the volume and quality of their semen.
Here, speaking to medical blogging site The Hippocratic Post, experts explain the devastating effects of male feminisation – and theories on its cause…
An increasing number of baby boys in the UK are being born with genital disorders.
One in 350 male babies have a condition known as hypospadias.
Instead of the opening of the penis being at the tip, it may be lower down the penis or even around the scrotum.
In a few rare cases, there may not be an opening at all.
Other disorders of the male reproductive system are also on the increase.
Cryptorchidism is the most common genital malformation of all, when one of both testes fail to descend into the scrotum, affecting between two and four per cent of baby boys.
Chordee – a downward curve of the penis, especially when erect – is usually, but not always, associated with hypospadias.
As the foetus develops, the urethra does not grow to its complete length.
Also during foetal development, the foreskin does not develop completely, which typically leaves extra foreskin on the top side of the penis and no foreskin on the underside of the penis.
Professor Richard Sharpe, a male-fertility specialist at the Medical Research Council’s University of Edinburgh Centre of Reproductive Health, suggests that all the disorders stem from a problem arising at the key stage in the development of the male foetus during early pregnancy.
He said: ‘From epidemiological studies, we know that each of the disorders is a risk factor for all the others, and that they share several pregnancy-related risk factors.’
‘Most importantly, we know that they share hormonal risk factors, in particular anything that interferes with the production or action of androgens and testosterone [the male sex hormones] during the sexual differentiation process of the foetus that occurs in the womb.’
In other words, the suggestion is that there is something happening early in the development of the male foetus that interferes with the key steps enabling it to develop into a healthy, fertile male.
Professor Neil Skakkebaek, of the University of Copenhagen, revealed in 2010 that sperm counts had fallen by about a half over the past 50 years – and more men were producing abnormal sperm.
Since the discovery, environmentalists have suggested that it could be ‘gender-bending’ chemicals – endocrine disrupters – in the environment that are the cause of the gradual feminisation of men.
But despite intense research to find these endocrine disrupters, the precise reasons for the problems have not so far been identified.
Some scientists believe that the culprit may just as likely be a change in lifestyle, rather than exposure to some new environmental chemical.
John Ashby, from the Syngenta Central Toxicology Laboratory in Macclesfield, said the focus on an environmental cause may be quite wrong.
‘The human [reproductive] conditions cannot at the moment be associated with a named chemical,’ Mr Ashby said.
‘There are many lifestyle changes that could be contributing to these conditions, for instance increased smoking among young women.’
Fat is linked with oestrogens – the female sex hormone – and more fat means more oestrogens, which means a possible increase in the risk of interference with the proper development of male reproductive organs.
‘The trends on dietary fat are up, and the implications are great for endocrine disruption,’ Mr Ashby said.
Nevertheless, work on animals has led to the discovery of some chemicals in the environment that could be playing an important role.
Professor Sharpe cites his work on chemicals called phthalates, substances used by industry to soften plastics.
He has been able to create a set of disorders in laboratory animals that mimic human testicular dysgenesis syndrome – where the male reproductive organs don’t develop properly – by exposing pregnant mothers to certain phthalates at a key stage of foetal development.
‘Phthalates are the most common environmental chemical. They are in the air around us,’ Professor Sharpe said.
However, he points out, it is too early to jump to the conclusion that this is the cause of the problem.
He continued: ‘At present, doses that are 100- to 500-fold higher than the highest reported human exposure are required to induce such effects, and we do not have any proof that phthalates can induce such effects in humans.’
‘Nevertheless, phthalates are everywhere in our environment, we are all exposed, and the highest exposure appears to be in young women of reproductive age.’
But although the jury is out in terms of what is causing the reproductive problems among humans, the same is not the case for the feminisation documented among wildlife, according to Professor Peter Matthiessen, an independent consultant ecotoxicologist.
‘People are cautious about saying that there are definite effects on humans, but we have hard evidence for effects on wildlife in all groups, from invertebrates to mammals,’ he said.
‘It’s a real-world issue, not just a theoretical worry. It’s actually happening.
The effects range from relatively trivial biochemical changes, probably of no ecological significance, to huge changes in populations and communities of organisms.
