Fri Apr 19, 2002
By EMMA ROSS, AP Medical Writer
LONDON - Couples are more likely to have a girl than a boy if either of the partners smoked heavily while they were trying to conceive, new research suggests.
Some scientists consider the ratio of male to female births to be an indicator of a population's health, because male sperm and embryos are more fragile than their female counterparts.
The study published this week in The Lancet medical journal is the first to propose that smoking may play a role.