A young generation of women is discovering a new brand of sexy in the most unlikely of places: their grandmothers’ underwear drawers.

“When I walk into a lingerie store, I’m always like, ‘O.K., which drawer in here is for the grannies?’ ” Daphne Javitch, 35, said of her predilection for ample-bottomed undies. That preference led Ms. Javitch, back in 2010, to found Ten Undies, a line with a cult following that sells cotton full-bottom bikinis, boy shorts and high-waist briefs not unlike the kind immortalized in “Bridget Jones’s Diary.” (“Hello, mommy.”) Ten’s wares are comfortable and practical, to be sure, but that’s hardly the only draw.

“Within millennial and Generation Y consumer groups, it’s considered cool to be wearing full-bottom underwear,” said Bernadette Kissane, an apparel analyst at the market intelligence firm Euromonitor. “Thongs have had their moment.”