When Maggie Betts wore a $400 pair of black silk pants to a formal family dinner, her mother was appalled. "She said they looked like sweatpants," the New York filmmaker recalls. A friend accused her of wearing "droopy drawers," while her cousin said she resembled Luke Skywalker.

"I feel like I look very chic in my harem pants," says Ms. Betts, 34 years old, of one of this fall's hottest fashion trends. "Anybody who makes fun of me doesn't know the truth and is a loser."

Harem...