New research reported by Japanese and Danish scientists in The Lancet medical journal in April 2002 showed that couples who smoked around the time their child was conceived were less likely to have a son.

         “If the father smokes more than 20 cigarettes a day and the mother does not smoke the sex ratio is significantly decreased with fewer boys than girls,” Professor Anne Crete Byskov, of University Hospital of Copenhagen, said in an interview. If both parents smoke the chances of producing a male child are even lower. Byskov and Dr  Misao Fukuda of  the Fukuda  Ladies Clinic in Hyogo,      Japan, coconducted the study. They studied the smoking patterns around the time of conception of the parents of 11, 800 Japanese infants.

        They are not sure why smokers produce fewer boys, but they suspect that sperm carrying the y chromosome for male children may be more susceptible to the effects of tobacco which could make it less likely to fertilise the woman's egg.