I'm on the same side as you. That makes no sense to me. Most guys clothes now-a-days look girly anyways, and most teenage boys wear girl skinny jeans. Just tell him that most of the older boys wear girl jeans and he will most likely think it's cool, also you wouldn't be lying. But, I also understand his side, not only are they "girl's clothes" (which I don't think matters.) they are also his older sister's clothes, which probably aren't what the kids are wearing now and he most likely just wants to fit in. But if he wants to go to school in his pajamas, let him, as long as it's not against dress code it doesn't really matter, they're the same as sweat pants, they just have pictures or a designe. I wear my pajamas to school all the time, though I am a girl. Oh well, if he wont accept the pants that's his fault, you were just trying to do the nice thing, if he can't accept it that's his problem.