We are flying through IAH this week, too, but terminal A. We flew through there a couple of months ago, and there were two separate lines. We just took the kiddos and went for the line with the normal metal detector. I've noticed they are more strict on babywearing, too. (And they refused to believe that DD's carseat wouldn't fit through the xray machine, despite the fact that I've carried it through that exact terminal at least a half dozen times. It got stuck in the machine when the TSA agent tried to jam it through, holding up everyone.)
I'm flying alone with the two kids this week, and I'm pregnant. If I get forced into the scanner or a 20 minute wait for a pat down, I'll probably lose my mind.
Oh, and I always fly early morning through IAH, and it seems like getting through security is as painless as it can be around 5 or 6 am. There's usually not a huge line, and I've never seen them make a big deal of the body scanner for anyone. (Again, we always fly through terminal A though, so it may be different at other checkpoints.)