Today, he rents a 10-by-10-foot room by himself. Like his personality, the room is split between the adult world and the baby world. His nursery side has a crib and a high chair. The other half is "more or less" a living room with a television, deep-freeze, lounge chair and his computer.
His favorite pastimes are watching children's cable channels and listening to kid's music. He also likes to play with Lincoln Logs and Play-Doh. Last year he met another adult baby in his hometown and they have fun playing together.
He has met others in online communities dedicated to the art of playing baby and baby mommy. The two most popular websites are Daily Diapers and ADISC, for those who love diapers and need support in their obsession.
The biggest challenge for Thornton is the realization that others outside these communities think he is weird.
"When I try to talk to someone about it who hasn't heard of it, my mind jumps around trying to explain what really is going on -- that it isn't a problem, like they think it is," he said.
"I tell them I sit down and enjoy role-playing for an hour or two a day to relax," said Thornton. "I tell them it's basically coloring, playing with blocks and watching kids' movies."
One neighbor who hadn't known about Thornton's life style was sympathetic when she learned about it while helping him move.
"She took it pretty good," he said. "She was open-minded and we talked."
They have been good friends ever since.
"I am fine right now," he said. "Accepting it has made me a happier person than if I try to deny it."
Stanley says he has never been in love, but he would love to find someone to marry.
"I'd like to become a dad some day," he said wistfully. "I'd like to look for someone to settle down with and have a family."