Smokers' sperm less fertile

MEN who smoke are less likely to make a woman pregnant than non-smokers, and the more they smoke the worse their chances are, a new study finds. Researchers from the American State University at Buffalo School of Medicine say that male smokers experience changes in their sperm that make fertilisation difficult. Lead author Lani Burkman, an associate professor in the department of gynaecology and obstetrics, said earlier studies had shown that when nicotine and its byproduct, cotinine, were added to sperm in the lab, they changed the way the sperm moved. The smokers' sperm were able to break down the egg wall but they were much less able to make a good bond. "If the tail is very weak, it will never push itself rough the zona," Dr Burkman said. The study estimated that the sperm of chronic smokers (smokers of four or more cigarettes a day for at least two years) were on average 75 per cent less fertile than those of nonsmokers.