Can the sex be determined at 12 weeks?

Really this depends on the doctor you go to, the ultrasound machine they use and the experience of the sonographer. Other factors include the build of the mother; (sometimes it is harder to tell when the mother is overweight due to extra fatty tissue) and how the baby cooperates during the scan. Most women are told the sex cannot be  recognized until around 18-20 weeks and that may be true for that doctor or that mother. I have 3 children and I found out the sex of all of them at 12 weeks and some days. I was told the reason for this was the high tech ultrasound machine at my perinatologist's office and the highly skilled sonographer. The machines are a little more stonger than the ones at regular ob offices. The genitalia does not look the same at 12 weeks, my husband could even tell the difference from the ultrasound.