I've always found both leggings and yoga pants to be VERY attractive and revealing in a sexual sense for sure, and I've always felt like ALL guys agree, and MANY girls don't even realize. I'm sure plenty do though, and they flaunt it. They flaunt it quite well. +1 for... no you know what...+2 for Yoga Pants in my book.
I do see the concern of underage girls wearing them however, should not be letting their underage daughters to be wearing such tight and revealing pants. I wouldn't let my teen daughter wear them for sure, its almost like they're asking to be looked at in a sexual manner.