This baby was on the lower end of the "normal" spectrum. Around 600 at 4w6d (which is certainly lower than I see a lot of women share, though perfectly within range according to data). Combine that with very mild symptoms (there IS a valid correlation between HCG and morning sickness) and also the fact that I conceived right on ovulation day-- and I was convinced there was no way this baby couldn't be a boy. But nope. At least 4 ultrasounds have I indicated that she's definitely a girl, and while they weren't specifically looking at the other two, no boy bits were anywhere to be seen.
I honestly think it could go either way. Best of luck to you!