The belief that the baby's heart rate can predict its gender is just a myth and has no scientific basis. The average fetal heart rate ranges from 120 to 160 beats per minute, regardless of the baby's gender. Many factors can influence the baby's heart rate, such as maternal activity level, gestational age, and even time of day. If you want to determine your baby's gender accurately, consult with your healthcare provider for reliable methods like ultrasound or genetic testing.