I had a 3d at 17 weeks 1 day. I didn't ask for it, but my doctor does everything (he is the one that does the ultrasound, so he switched from the 2d to the 3d). It was AMAZING! I could see little one's face, and at first he had his hand over his eye. Then he put his hand down and opened his mouth several times... It was the first time I relaxed a little bit (I'm a little too worried about things... Guess that's normal). I knew baby was a boy beause my doctor told me at 13 weeks and said he was 100% sure. Anyway, if you can pay for it, I'd recommend it. :)