Last week my MW also said something about the heart rate and how some say it's a sign of a girl but then she brushed it off with "but that stuff's not always true".
I am convinced we have a boy, I don't know why. I just see us having a boy with this pregnancy. Maybe because DH's sis has two girls and I feel like his family is due for a boy. Even though I would love a girl. And especially love what*ever* I have. But we went for our 20 wk anatomy scan today. We told the technician we absolutely did not want to know the sex. When she told us to turn our heads so she could check out the anatomy, she said very quickly, "ok, I've got the sex" so to me that means boy parts because I was always under the impression it's easier to identify boy parts than girl parts. So the fact she said it so quickly tipped me off. But we'll see 
Most importantly, just REALLY glad the scan went well,no Downs indicators (we chose to not do the nuchal), no cleft plate, all organs good to go, healthy heart and all. Phew.
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