Takashi Sakai is a healthy 41-year-old heterosexual man with a good job and a charming smile. But he's never had sex, one of a growing number of middle-aged Japanese men who are still virgins.

Sakai has never even had any kind of relationship with a woman, and he says he has no idea how he might get to know one.

"I've never had a girlfriend. It's never happened," he said. "It's not like I'm not interested. I admire women. But I just cannot get on the right track."