At how many weeks can you find out sex of baby. went in at 13 weeks & doctor said 85% it was a baby boy ?

18-22 weeks: Ultrasound is fairly accurate and is the least invasive way to find out if you are having a boy or a girl. This procedure is most accurate during the 18-22nd weeks of your pregnancy. Prior to this time the baby may not be well enough developed to get an accurate answer with a gender ultrasound. After this time the baby is more crowded making it more difficult to get a good view.

Depends $$$: You can have a test run on your blood where they can find rare fetal cells and study them.The NIPP, a test originally designed to study paternity, can be done as early as 8 wks and tell sex and many other things.It is expensive and not covered by insurers. Boy parts are complete no later than 12 wks but ultrasound studies may not be very accurate until 16-18 wks or so.