Moreover, gay men who have children do so an average of three years earlier than heterosexual men, census data shows, Mr. Gates said. At the same time, there are fewer white women of childbearing age nationally, according to demographers, while the number of minority women of childbearing age is expanding.

Jacksonville was a magnet for Ms. Maffett even before she moved here. While its gay residents remained largely hidden, it had a gay-friendly church. In 2003, she spent her Sundays driving 90 minutes each way to attend from the town where she worked as a school bus driver.

Ms. Maffett appreciated the safety of the church in Jacksonville. Her father was a Baptist preacher, and her former husband was a member of the Church of Christ, so she knew how unwelcoming some churches could be for gays. Even so, she felt little connection to the gay congregation in Jacksonville  mostly white, male and childless.

“The pastors were all white guys,” said Ms. Maffett, who is black. “They were nice to us, but we weren’t really feeling that they knew how to cater to kids.”

Then she met Valerie Williams, a customer service worker with a sunny personality and a booming voice. Ms. Williams, 33, had been part of the city’s gay community for years, and when the first African-American, gay-friendly church opened in 2007, she thought it needed to go one step further.

“People were looking to do stuff with their kids, and they had no place to go,” she said.

So last summer, Ms. Williams became pastor of St. Luke’s Community Church, one of the oldest gay-friendly churches in the city, and immediately set up a youth program. Attendance by the mixed-race congregation swelled to more than 90 from 25 in just a few months.