LONDON: Pregnant? Well, it's a great time to quit smoking if you want a healthy child, otherwise you might end up harming your baby boy's fertility.

Researchers at the University of Aberdeen in the United Kingdom have carried out a study and found that smoking reduces the sperm count in babies whose mothers are addicted to puffing fags even during pregnancy.

According to the researchers, smoking halves levels of a key testis gene that helps sperm count, and this creates problems in the development of testicle in baby boys who may end up having abnormal penis.

"The gene that plays a key role in normal male development has been linked to maternal smoking and fertility problems," the Daily Mirror reported, quoting lead researcher Prof Paul Fowler as saying.

In fact, Prof Fowler and his colleagues came to the conclusion after analysing the effects of smoking on a group of mothers during their pregnancy and their newborns over a period of time.

"It reinforces the very clear message that women should not smoke during pregnancy," fellow researcher Prof Siladitya Bhattacharya was quoted by the British tabloid as saying.

The UK study came just days after researchers in the United States had warned that moms-to-be who drink alcohol are more likely to cause bad behaviour in their children.

In their study, the American team found that for each additional day of the week that mothers drank alcohol during pregnancy, their children had an increase in conduct and impulsiveness problems than those kids whose mothers did not drink.