A professor of neurobiology at Amsterdam University has written a book, citing multiple academic studies, claiming that a mother’s lifestyle can predict the adult life of her baby.
Dr. Dick Swabb says that pregnant women who smoke or lead a stressful lifestyle are more likely to have children who are gay adults.
"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 fetal sex hormones,” Swabb says.
He said the fetal brain begins developing at two weeks and any toxin introduced into the mother at this time impacts the baby’s developing.
"Pre-birth exposure to both nicotine and amphetamines increases the chance of lesbian daughters," he told the Sunday Times.
He cited a study of women taking synthetic estrogen from 1939 to 1960 to reduce the change of miscarriage. Their daughters had greater probability of being bisexual or lesbian.
Swabb says drinking and taking drugs can also lower the I.Q. of the child.
"In women who drink a lot, cells that were meant to migrate across the foetal brain can end up leaving the brain altogether," he said. "Even in women who drink just a glass of wine a day we see effects [such as] lower IQ and hyperactivity. There is no safe level."
Swabb believes that research proves that child development during pregnancy is directly responsible for adult lifestyles.
Other research has suggested that males with older brothers are more likely to be gay. For each older brother a man has, his odds of being gay increases 33 percent, according to Canadian psychologist Ray Blanchard.