There is no concrete research to suggest the whether the baby is boy or girl if the fetal heart rate is above 150 BPM. It’s a myth that has been propagated by various resources. Recent research has suggest there is no absolute difference by which we can identify a male fetus or female fetus depending upon a Baby’s Fetal Heart rate in BPM (Beats per minute)
But the same study also suggests there will be only minor difference between male fetus and female fetus in terms of heart beat. In nearly 9000+ cases they were able to find only a find only a baseline difference of 0.9 beats/min between the male and female fetuses.
If anyone says that one can tell a gender of baby by it’s heart beat above a certain level then say to them it’s a purely myth as there is no concrete scientific research papers that proves that!