A Newcastle University study involving thousands of families is
helping prospective parents work out whether they are likely to
have sons or daughters. The work by Corry Gellatly, a research
scientist at the university, has shown that men inherit a
tendency to have more sons or more daughters from their parents.
This means that a man with many brothers is more likely to have
sons, while a man with many sisters is more likely to have
daughters. The research, published online by the journal
Evolutionary Biology, involved a study of 927 family trees
containing information on 556,387 people from North America and
Europe going back to 1600. "The family tree study showed that
whether you're likely to have a boy or a girl is inherited. We
now know that men are more likely to have sons if they have more
brothers but are more likely to have daughters if they have more
sisters. However, in women, you just can't predict it," Mr
Gellatly explains. Men determine the sex of a baby depending on
whether their sperm is carryi