how far along in pregnancy until you can know sex of baby
9 out of 10 found this helpful. You have to be between 16 and 20 weeks to find out the sex of the baby. That is when the genitals transforms into what the baby is gonna be. At 20 weeks they can be pretty sure of what sex the baby is. The baby can still be trick the md though. posted 09/13/2008 by Nursenatashao.