A neuroscientist from Amsterdam University claims that a pregnant woman's lifestyle has a great impact on the unborn child's IQ and sexuality.

Neuroscientist Dr. Dick Swaab has said that women, who smoke and drink or are stressed during pregnancy, are more likely to give birth to kids who are homosexuals. Swaab's statement has added fuel to an ongoing debate over the origin and exact cause of homosexuality.

The theory proposed by Dr. Swaab suggests that the lifestyle of the pregnant woman affects the development of the baby. According to Swaab, smoking or taking synthetic hormones elevates the chances of girls being bisexual or lesbians.

He said that the chances of raising lesbian daughters are high if the mother used amphetamines and nicotine during pregnancy.

The chances of boys turning into gays largely depend on the number of older brothers; higher number of older brothers doubles the risk of boy being gay. According to the researchers, development of the mother's immune response to male hormone gets stronger every time a male child is born, source Sydney Morning Herald.

Dr. Swaab, who presented his views to Britain's Sunday Times, strongly believes that the sexuality of the child is determined in the womb and cannot be altered, contradicting previous theories that claim sexuality is affected by the upbringing or the selected lifestyle they choose.

In his new book 'We Are Our Brains', Dr. Swaab has highlighted several academic studies conducted during the years 1939 -1960 that focused on how the pregnant mother's lifestyle affects the child. Those women who took synthetic estrogen to lower the risk of suffering a miscarriage had a high chance of having a daughter who was a lesbian or bisexual.

"Pre-birth exposure to both nicotine and amphetamines increases the chance of lesbian daughters," Swaab told Britain's Sunday Times. "Pregnant women suffering from stress are also more likely to have homosexual children of both genders because their raised level of the stress hormone cortisol affects the production of foetal sex hormones."

Also residing in a highly pollulated area increases the risk of autism in the kid, he said.

He concludes saying that lifestyle is a small fraction that influences the development of the fetus and that genetics play a major role.