Old wives tales about baby"s heartbeat, Boy or girl? Do you think there is any truth in the old wives tale?

I Know its just a wives tale and might be inaccurate, however I was wondering how many people actually believe it to be true and has it come out true or false for you. If the heart rate is low its a boy if its high its a girl. I'm 16 weeks and my baby"s heart rate was 152 (ultrasound @10 weeks). 148 (ultrasound @ 12 weeks) and now today 16 weeks without ultrasound the Dr said its in the 130's she didn't give a specific rate, but the Doppler was not digital so she had to count. so I'm thinking according to the old wives tale that I am having another boy. My son's heart rate through the whole pregnancy was around 135.