A: Prediction of the sex by fetal heartbeat is just a guess, plain and simple. There is no difference in the heart rate pattern of male and female babies.

Over the past 20 years I have listened to patients try to guess their babies' sex based on a variety of old wives' tales. In fact, there are only a few ways to determine it.

In many cases ultrasound can distinguish the sex, though I caution my patients about trusting the results. On occasion an ultrasound reading gets it wrong, in which case a pink room gets a quick coat of blue paint or vice versa.

The only tests that are 100% accurate are amniocentesis and a chorionic villus sampling. However, these tests are only performed for medical reasons, not just for sex determination.