BPM (heartbeat) a real sign of Gender?!

Carina
This is my second pregnancy. And with the first the BPM was 138ish and I had a little boy. 
This pregnancy (10w3d) the heartbeat is around 155bmp. 
Is it a wives tale about the heartbeats being an indicator to gender or is it proven to be correct?! 
What is your little ones BMP/heartbeat and if you know the gender post it as well!!