During both of my pregnancies, my babies' heart rates hovered around 140 at every checkup, the number that folklore says can predict whether the baby is a boy or a girl. A faster heart rate means you're having a girl, they say. A slower heart rate, a boy. So after a while, it meant little to me whether the tale was true or not. My babes stayed stubbornly right on the line, every checkup.

A study published in the British Journal of Obstetrics and Gynecology that involved 79 pregnant women could not find a link between fetal heart rate and gender. Instead, they say that fetal heart rates all seem to follow the same trend. They start out at about 85 beats a minute, raise quickly to 175 beats early in the first trimester, then slow back down to an average of 120 to 160 beats a day.

What do you think? Does the method work? Or does science trump tradition?