Q&A: How Soon Can You Find Out Baby’s Sex?


How soon can I find out my baby’s sex? I know you can sometimes tell by using ultrasound, but are there any other reliable methods that are used?


    This is one of the most common questions I receive from parents-to-be. Most patients undergo an ultrasound at around 18-20 weeks (about four and a half to five months). Normally, at this stage of pregnancy we can determine the baby’s sex, but not always. The position of the baby during the ultrasound is the most important aspect in our ability to tell the baby’s sex, andthere’s no way to influence that. For obvious reasons, it’s usually easier to see if the baby is a boy.

    One reliable method is using amniocentesis to check the baby’s chromosomes. This test is usually performed on a mother who is 35 years or older, for the purpose of identifying possible genetic problems. It involves inserting a needle into the uterus to remove a small amount of amniotic fluid. We usually do this test at around 16 weeks, so in this instance, the mother can find out the baby’s sex a little sooner. This test isn’t without risk, however, and isn’t generally performed simply to determine the baby’s sex.

        Another test that can look at the baby’s chromosomes is called CVS (chorionic villus sampling), which is performed during the first trimester to look for problems with the baby’s chromosomes. However, this test is infrequently used.

        I’m often asked if you can tell the baby’s sex by the heart rate — on the myth that one sex is faster than another — but that is just an old wives’ tale. Some people claim they can tell the baby’s sex by the way you’re carrying, but, again, there is no scientific proof that this is true. Still others use a “pendulum test” in which an object is suspended over the pregnant belly and the baby’s sex is predicted depending on which way the pendulum swings. Again, there is no documented proof that this test works.

        Don’t get frustrated if the doctor can’t tell what the baby’s sex is on ultrasound. You’ll know soon enough. In the meantime, just buy green or yellow clothes and accessories!

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