PREVIOUS EVENTS

We all know how babies are made …but what what are the odds of having a boy?  50-50? The moment any child is born we know whether it is a girl or a boy.  Anyone who has had a child since the recession before last will know that the sex of a child can be determined on an ultrasound scan at 12 weeks, but of course the embryo is already either male or female when it is an unrecognizable cluster of cells.
What factors make it more likely that a bunch of flowers – stay for a coffee – failure of contraception will result in a baby boy 9 months later rather than a baby girl?  Why do some couples have more boy children, and others more girls?  Why are there clusters of boys born at certain times?  Does evolution have any effect on whether more children are girls than boys?
Dr Corry Gellatly of the Evolutionary Biology Group at Newcastle University has been studying the possible genetic reasons that explain why a particular baby is more likely to be a girl, or why a population may be full of boy babies.