Smoking = XX

A team from the Valencian Infertility Institute in Spain have found that 73% of embryos fertilized by men who smoke more than 20 cigarettes a day are female. Apparently, tobacco favors the X chromosome when it comes to fertilizing an embryo. However, nicotine in women does not effect the sex of the embryo.

Now there´s a good reason for men to smoke more and women to smoke less.

Source: 20 Minutos, Madrid, Spain, 06/17/2005, Pg. 9