Its an old wives tale and not true at all. It's always a 50/50. My sons heart rate has been in the 150's my whole pregnancy, and at 39 weeks he's still a boy.
No I think it depends on the person. Like with my mother in law all her girls were in the 160s and her boys were 140s. Mt baby is in the 140s and we think its a boy, but we are not finding out.
My baby's heart beat was 144 when I got my sonogram and I'm having a boy.
Mine has range from 144-159 its a boy the only way to know is to see it..
My baby girls heartbeat was higher then 140,