Gender Ultrasound Timing Technicians observe your baby's genitalia as part of a routine anatomy scan, which takes place in the second trimester, usually between 18 and 22 weeks.

How can you predict gender from a 12 week ultrasound scan? According to proponents of nub theory, you can work out your baby’s sex at a 12-week ultrasound . Read More on Parenting ...

The average heart rate for baby boys in the first trimester was 154.9 bpm (plus or minus 22.8 bpm) and for baby girls it was 151.7 bpm (plus or minus 22.7 bpm). In other words, this myth is busted.