Nub theory question

At my NT scan, the tech tried to get a good picture of the baby's nub, but couldn't. With my girls it was super easy to get their nub shots. This baby was sleeping the entire ultrasound, and the tech said that its leg was in the way. My doctor even tried and he couldn't get it (he's crazy about nub theory, lol.)

Now, my doc told me that the baby might be a boy because he was having trouble getting a good shot of the nub because baby's leg was in the way. Does this in any way make sense? He said something about girl nubs being more fixed at that point (According to measurements I was 13 weeks, by my earliest scan I was 12w5d).

I'm so curious to know. Like I said, my girls were pretty clear nub shots...this one was trouble, heh.

http://sphotos-a.xx.fbcdn.net/hphoto...32218267_n.jpg
I added a photo, maybe someone can see it better than any of us can, lol

Well, if they couldn't see it, the leg could block it either way. I can only assume that the leg position was one that a flat nub sticking out above the spine could be seen but if pointing straight up the leg was possibly blocking but that is a stretch. If nobody saw it, 50/50.