Pubdate: Thu, 05 Jun 2014 Source: Scotsman (UK) Copyright: 2014 The Scotsman Publications Ltd Contact: http://thescotsman.scotsman.com/contactus.aspx Website: http://thescotsman.scotsman.com/ Details: http://www.mapinc.org/media/406 Author: John Von Radowitz Page: 15 CANNABIS SMOKERS IN FERTILITY WARNING SMOKING cannabis can reduce a man's fertility by altering the size and shape of his sperm, research shows. More surprisingly, sex in the summer months has a similar effect, scientists found. Conversely, abstaining from sexual activity for more than six days improved the "morphology" of sperm. However, common lifestyle factors including smoking cigarettes and drinking alcohol had little effect on sperm quality. When less than 4 per cent of a man's sperm has a normal size and shape, statistics show he will find it harder to father a child and may have to attend an IVF clinic. Dr Allan Pacey, senior lecturer in andrology at Sheffield University, said: "If you're trying to have a baby, pay attention to the risks. If you're a habitual cannabis user, stop, and you need to stop for at least three months." The study, the world's largest investigating the effects of lifestyle on sperm morphology, recruited 2,249 men from 14 fertility clinics around the UK. Scientists compared information from 318 men with less than 4 per cent normal sperm and 1,652 whose sperm was higher quality. Men in the first group were nearly twice as likely to have used cannabis in the three months before giving a sample, if they were aged under 30. They were also nearly twice as likely to have produced a sample from June to August. Dr Pacey said the summer influence was unexplained but did not appear to be linked to heat. - --- MAP posted-by: Jay Bergstrom