My son was so reliably 165 beats per minute that we called him "Little 165" for a while. The heart rate does not tell you if it's a boy or girl.
I agree with Clysta. I don't trust the vives tale.
Heartbeat doesn't tell what the sex is. It's an old wives tale. Supposedly, anything above 140 is a girl and anything below 140 is a boy, but my daughters was generally 135 and below. It also depends on if baby is resting or moving around. If they're resting, it will be lower and movement will make it higher.