Normally, you can opt to find out the sex of the baby at the 20-week ultrasound, as the genitals are visible starting around the 12-week mark. If you’re comfortable with bloodwork, you may be able to find out the sex after nine or ten weeks. The caveat is that this test - called an NIPT - is primarily for genetic conditions, so you can’t get one just to find out the baby’s sex unless you pay for one privately.