Don't smoke if you want a baby boy
A research done in UK reveals that parents who smoke when they conceive a child will have a higher chance of giving birth to a girl instead of a boy. From Independent:
The research, by a team of paediatricians led by Professor Bernard Brabin, found that substances contained in cigarettes, such as nicotine, inhibit sperm carrying male chromosomes from fertilising eggs.
"The study aimed to assess whether maternal smoking during pregnancy affects the likelihood of the offspring being male or female. When we adjusted for factors statistically like maternal age and if both parents smoked they had almost double the chance of having a female baby," said Mr Brabin, professor of tropical paediatrics. "We don't know what causes it. The hypothesis is that sperm cells carrying the Y- chromosome which are responsible for male children are more sensitive to unfavourable smoking related changes in the mother. Smoking reduces oestrogen and causes changes to the mother's cervix. The message is clear: if you want an increased chance of a male baby, don't smoke during pregnancy."