Wives tale on heart beat

Rebecca • Married to my high school sweetheart. Currently have 2 children Xavier Cole and Mariah Nicole.
I am curious if the old wives tales on the heart beat is true or not. It claimes if the heartbeat is below 160 it's a boy and above 160 is a girl. So far it was true for my first child. His heartbeat was 153. This pregnancy it's 160 exactly and I don't know what it is just yet.