What's the right fashion statement to make when you're Ralph Lauren's son? "I wear my father's clothes my own way," says David Lauren, who pairs the preppy basics of Dad's designs with vintage touches. "It's about finding my own identity in a world he helped create."

Achieving similar balance in his career is tougher, but lately Lauren, 32, feels confident he's getting there. The founder of the now-defunct gen-X magazine Swing is senior vice president of advertising and marketing at Polo Ralph Lauren—and the man some predict will take over the reins one day. This fall he launched an ad campaign featuring activists urging people to take up volunteerism. The ads promote G.I.V.E. jeans, 10 percent of whose profits will go to charities like Teach for America.

"My parents grew up in The Bronx without money, so I always respected people who believed in giving back," says Lauren, who—like siblings Andrew, 34, a film producer, and Dylan, 29, a candy-store-chain magnate who "gives me a lot of advice"—enjoyed a privileged Manhattan upbringing. Ralph (himself a philanthropist who recently pitched in with his sons to help repaint his old elementary school) couldn't be prouder. "David," he says, "is an honest, sincere person who cares about other people."

To date, those people don't include a wife. Tip to interested parties: Sporting head-to-toe Polo isn't the surest way to this heir apparent's heart. "When I meet a girl who tells me she volunteers," David says, "I think it's incredibly sexy."