How early can the sex of the baby be determined by ultrasound? I have an appointment on day 138.
At 138 days, you're approximately 19 to 20 weeks. The gender can usually be determined if your baby cooperates. Your baby needs to be sitting in slighty indiscrete positions to catch a tell-tale sign of male or female gender. Certainly, the farther along you are, the more likely you'll see something of note, so if you wanted to hedge your bets, wait another month.