Marc Goldstein, professor of urology and director of the Center for Male Reproductive Medicine at New York Hospital's Cornell Medical Center, said yesterday that the optimum temperature for sperm production is 32C to 33C. Anything higher is likely to hinder it. Sitting with legs crossed for 20 minutes while wearing trousers raises the average temperature to between 36C and 37C.
"Temperature is a very important factor in testicular function, and 2,000 years ago the Japanese used hot baths as a form of contraception. Anything above the optimum temperature could be detrimental,'' said Professor Goldstein.
"Just one or two degrees is significant, and we advise men who want to have children to avoid long baths, saunas and Jacuzzis. We also suggest they don't sit at the desk all day with their legs crossed and that they keep the bedroom cool at night.''
The jury is still out on whether wearing tight underwear and trousers can have a similar effect, although Professor Goldstein cautions against tight leather trousers.
One problem for would-be fathers with a penchant for crossing legs is that the effects are not immediate because of the long sperm production cycle.
"Sperm production takes 77 days. If there is testicular heating for a couple of days, it will not show up for two months or so,'' said Professor Goldstein.
Men who occasionally cross their legs are unlikely to be much affected, but chronic crossers who spend hours a day with legs folded could find their fertility impaired.Reuse content