This is one of the most common questions I get from parents-to-be. If you're dying to know whether to stock up on pink or blue onesies, you'll likely have to wait until you're about 18 to 20 weeks along. We can usually determine the baby's sex during a routine ultrasound visit at this time, but not always. The position of the baby during the ultrasound is key, and if your baby's curled up or facing the wrong way, you may have to wait until your next appointment. For obvious reasons, it's usually easier to see if your baby is a boy.
Moms-to-be who undergo amniocentesis -- a prenatal test that's used to check for certain genetic problems, usually around 16 weeks -- can also find out whether they're having a boy or a girl at that time. Usually given to moms 35 or older, it involves inserting a needle into the uterus to remove a small amount of amniotic fluid. But the test does carry a small increased risk of miscarriage, and it's not performed simply to determine your baby's sex.