Are my chances for having a girl gone?

Jessica
Just came from my doctors appointment and feel like I am having my third son because of the heartbeat. My first time I heard it, it was 178 at my 9 week ultrasound. Then when my doctor does the Doppler it has been 138 and  today 141.  It's going to be a boy isn't it? Anyone else with experience with this and it being a girl?