Mom holds key to son's fertility

Published Apr 19, 2010

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By Fiona Macrae

A man's fertility depends more on his mother's lifestyle than his own, research suggests.

A large-scale review of factors affecting sperm production found that how a woman looks after herself in pregnancy could have a major effect on her unborn baby's ability to father a child in adulthood.

Smoking and exposure to pesticides and traffic pollution all do more harm in the first weeks of life than in the adult body, according to Richard Sharpe, one of Britain's leading reproductive biologists.

Professor Sharpe also said that while damage done in adulthood can be undone by kicking bad habits, damage inflicted in the womb was probably permanent.

This could be because exposure to toxins in the womb cuts the number of sertoli cells, highly specialised cells needed to 'nurse' young sperm through to maturity during a man's adult life.

With as many as one in five men having a low sperm count and British couples spending almost ?2-billion a year at IVF clinics, the finding underlines the importance of a woman doing the best for her baby during pregnancy.

Professor Sharpe, of Edinburgh University, evaluated studies from around the world on the effects on male fertility of factors such as smoking, obesity and exposure to chemicals.

A study of the after-effects of a major chemical leak from an Italian factory found no effect on the sperm counts of men who were adults at the time. But those who were in the womb grew up to have lower-than-expected sperm counts.

The professor's research concluded that chemicals found in food, cosmetics and cleaning products are to blame for some of the birth defects to baby boys' genitals and are raising the risk of testicular cancer in later life. But evidence that the same chemicals affect a grown man is lacking.

Writing in the journal Philosophical Transactions of the Royal Society B, Professor Sharpe said: "There is a widespread belief that environmental pesticide exposures can adversely affect sperm production in men at large. However, this seems largely untenable.

"Overall, the present view is that there is no firm evidence that exposure of adult men to common environmental chemicals has any major impact on fertility."

Other studies have found that smoking in pregnancy cuts sperm count by up to 40 per cent. In contrast, a man who smokes heavily may have a sperm count only 10 per cent lower than normal.

But men cannot relax completely, with obesity and sedentary lifestyles both affecting their ability to father a child.

Dr Allan Pacey, a Sheffield University expert in male fertility, said: "This review reminds us that the sperm production capacity of men is probably established quite early in life and perhaps even before they are born.

"This highlights the importance of women having healthy pregnancies and not exposing their baby to harmful chemicals, such as cigarette smoke.

"Men can damage their sperm production and would-be fathers should try to lead healthy lives and limit their exposure to things that we think are damaging to sperm production - hot baths, and recreational and prescription drugs." - Daily Mail

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