A 3 ½-year-old named Harry was playing at home in Los Angeles recently when his father walked in with a Target shopping bag. Inside was a special gift for the little boy: a sparkly princess Barbie doll.

“You could hear the gasp of excitement,” recounted Harry’s mother, Lee. “It just made his whole world.”

A year ago, Harry found Barbies abandoned by his two older sisters. He makes sure they are properly outfitted and worshipped regularly. The girls’ cast-off dress-up clothes have become his go-to outfits. And when he arrives at preschool each morning, he selects a dress from the costume box and wears it through recess, even as he scrambles on the jungle gym.

At first, Harry’s father had a hard time watching his son twirl around in princess wear. But his gift of the Barbie symbolized acceptance; Harry’s joyous gasp indicated that the little boy intuitively understood. “We are following his lead and supporting him for who he wants to be,” said Lee, who, like other parents interviewed for this article, did not want to be fully identified in order to protect their children.