Heart rate boy or girl?!

Edwina
So I'm confused we are 12 weeks pregnant and heart rate is at 164 two weeks ago it was 174 I was thinking it was a girl but looking at my sons paperwork at 7 weeks  his heart rate was 170. I'm so confused on what we are having..... We got blood work done but my sister is the only one who knows till or reveal. Any insight would be awesome. Please help!