Gender of baby based on heart beat

Danielle

So I'm 9 weeks 4 days pregnant. I was trying to follow the Chinese baby callander as I really want a boy. I ended up getting pregnant and according to ultra sound it would have been December which callander predicts a girl. I truly want a healthy baby but I really dont want a girl. I have heard of that of the heart rate is avlvoce 150 or 160 it's a girl. Mine is 180 last week and 160 today. Has anyone found this wise tail to be true??