What is the earliest week i can you find out what sex my baby is ?

16 weeks?: 18-20 wks is the typical time to have the second-trimester ultrasound to assess fetal development and often you maybe able to determine the gender of the baby--sometimes we can't. If you are lucky, you may see it 16 wks, but most often it is quite difficult as female vs male parts are not too distinguishable very early on. Either way, you can't change it. Congrats on the pregnancy. Good luck.

10-12 weeks.: I can usually see the angle of the genital tubercle by 10-12 weeks by transabdominal sonography (even earlier by transvaginal scanning); that correlates >90% with ultimate birth gender. I hope your baby is healthy regardless of gender/sex - keep things into perspective.

How interested ??$$: You can actually get a gender determination with the NIPP, a non invasive test that identifies fetal cells in mothers blood. It can be done as early as 8-9 wks, is done mostly for paternity determination, and costs$$. Otherwise most wait until 18 wks or so when most are comfortable making the call from an ultrasound.