I went for a 4D ultrasound to find out gender out 15 weeks (last week). The lady said they baby was moving around so much she couldn't get any pics and couldn't do 4D because of that. She did say they have a "nub theory" they go by and she said baby appears to be a girl. I'm just wondering what's the percent of nub theory being right? Anyone have this happen and the "nub theory" be wrong? I go to my high risk Dr next week (I'll be 17 weeks) and hopefully they can confirm girl ..or boy lol!