The belief that fetal heart rate can predict the gender of a baby is a popular old wives' tale. However, there is no scientific evidence to support this claim. The average fetal heart rate ranges from 120 to 160 beats per minute, and it can vary throughout pregnancy. While some people believe that a higher heart rate indicates a girl and a lower heart rate indicates a boy, this theory has been debunked by medical professionals. The truth is, the fetal heart rate is influenced by various factors such as maternal activity level, gestational age, and individual variations. It is essential to remember that only an ultrasound or genetic testing can accurately determine the sex of your baby. So, while it's fun to speculate based on old wives' tales, don't rely solely on the heart rate for predicting your baby's gender!