Pastor Frank Schaefer never expected to speak for gay rights. His son’s gay wedding changed everything.

Lebanon, Pa. — To Frank Schaefer, it wasn’t three of his four children being gay that bothered him so much, it was that they looked gay. So sometimes he’d offer pointers.

“Swing your arms when you walk,” Schaefer’s son Kevin, then 16, recalled his father telling him one fall day a few years ago.

The Schaefers were window-shopping during a family trip to Boston when Schaefer had stopped Kevin and his sister, Debbie, who was three years older. “Not swinging is ladylike,” he advised Kevin.

He then pointed out to Debbie that she didn’t move her hips when she walked, like most women do. Maybe, he joked, the two could switch walks?

Kevin recalls being humiliated but not angry. He understood that his father was struggling with his own feelings. Debbie just brushed her father off. He wasn’t really criticizing, she told herself — he was just making an observation.

This painful scene between a parent and a gay child is perhaps not so unusual — until you widen the frame.

The next year, Frank Schaefer, a United Methodist pastor in rural Pennsylvania, was in Boston again on a family trip. This time, he was there to officiate at the wedding of his gay son, Tim — in violation of his denomination’s doctrine, which prohibits same-sex marriage.

The love of Tim and his soon-to-be-husband “is from no other source than from God,”Schaefer told some 120 people gathered that April day in 2007 at a restaurant overlooking the Massachusetts Bay. The applause seemed to go on forever.

It took six years for word of Schaefer’s actions to find its way to the Methodist Church. The church trial that followed a complaint to the bishop’s office made global news last year. In December, Schaefer’s defrocking ignited a movement that could well cause a schism in the country’s second-largest denomination, with a large group of conservative clergy a few weeks ago calling for dialogue on how to“part ways amicably.”

Meanwhile, Schaefer has become a national star in the gay equality movement — a sought-after speaker and the focus of a documentary, a play and countless stories in the news media. Yet even as he passionately advocates for gay rights, the 52-year-old Schaefer is an unlikely activist. Even now, years after the first of his three gay children came out, he talks about a continuing “evolution” in his beliefs.

All this makes the defrocked pastor an apt icon for America in 2014, when polls show a large swath of adults still have doubts about gay equality, despite the whirlwind embrace of the movement by the courts, governments and much of society.

“I was concerned, as many parents are, how people look at your children, that they fit in,” Schaefer says about the Boston sidewalk scene years ago. “I’m not sure there aren’t still issues deep down.”