If it sometimes seems like all your friends are getting pregnant around the same time, there may be a scientific reason.

A new Italian study finds women are far more likely to have a child in the two years after a high school friend gives birth.

Researchers believe it's partly because friendships forged in childhood have a big influence on the decision about whether to have a child.

They also suspect it's because, as they watch their friend go through the process, they get used to the idea and it eases any fears they may have.

There may also be an economic factor, since it's cheaper to borrow baby cribs, clothes and toys from friends than buy them.