Is it more difficult to determine the sex of the baby when the mother is over weight? I am roughly 260, I have lost 9 pounds so far throughout my pregnancy and I'm 21 weeks 2 days. Had a gender ultrasound at 16 weeks, tech said boy, dr said girl. Went for my anatomy scan at 18 weeks and was told boy. I got back November 9th (Monday) for another ultrasound to make for certain. Here's the ultrasound pictures at 18 weeks. What do you think?