Heartbeat theory

Heather • Mother of 2, soon to be 3. Happily married for 7 years. 💎👣💜🍼
My baby's heartbeat was 148 today. Does that mean boy or girl. My husband wants our last to be a boy. I've had people tell me it's a girl due to the rate, BUT I had heard that some people's baby's has between 140-155 and it was a boy. So are these old wives tales even true or no!?! Help me please! Give us some hope! I just want my baby healthy. But I would still even like a boy.