Looking at the Paris spring/summer runways, off-the-shoulder tops were a standout trend, from Chloé’s one-shoulder puff-sleeve dresses to Coperni’s sexy, sheer off-the-shoulder slips.

How young is too young for a crop top? It depends on who you ask. Walk into almost any store that carries kids clothing and you’ll find racks of midriff-baring sweatshirts and tees. The fashion ...