How soon can we find out the sex of our baby?

About 18 weeks: While fetal sex determination can be done as early as 10 weeks by chorionic villus sampling for dna testing - this is an invasive procedure not in general use. Ultrasound can be used to detect male genitalia on the fetus as early as fourteen weeks - but male parts may not be evident until sixteen weeks or later. Definitive female genitalia are not usually seen before sixteen weeks or later.

10wks: High resolution ultrasound in the hands of a well trained tech can sometimes pick up male genitals by 10wks. The regular ultrasound used to verify placental location & gestation is not likely to yield results until later.If the kid doesn't cooperate you may be surprised at delivery.