boy ultrasound with three lines?

Ultrasound Signs for Determining Baby's Sex
By Robin Elise Weiss, PhD, MPH
Updated on June 14, 2021
Medically reviewed
by Andrea Chisholm, MD
If you have chosen to find out the sex of your baby, you are most likely going to do so via ultrasound. Typically, the ultrasound is done halfway through the pregnancy.