Maybe it is my MCN's, a few people have said the same...I use Abby Gro's. They probably are a little bulky, but I love 'em!
I tried the 'one size up' and that seems ok, but if he's in sposies to go out I'll have to change his pants as they just fall off him, lol! And the legs need folding too, not that that's an issue.
Not sure about leggings for a boy...