For years, Delman Coates wondered about his cousin, the childhood playmate he used to see at family get-togethers. The two went off to college and lost touch. Then, Coates learned from family members that his cousin was gay and had contracted HIV.

Within the family, neither issue was discussed openly.

But Saturday, 20 years after he last saw his cousin, Coates tracked him down by telephone in South Carolina and chatted for an hour during an emotional conversation.

“I apologized for participating in this conspiracy of silence,” said Coates, senior pastor at the 8,000-member Mount Ennon Baptist Church in Clinton.

The day before the call, Coates, 39, also spoke up when he testified with Maryland Gov. Martin O’Malley during a contentious hearing in Annapolis in support of a bill legalizing same-sex marriage. Coates is among few African American preachers in Maryland who support the bill, which puts him at odds with the majority in the black community, particularly in his home county of Prince George’s.

In a Maryland poll conducted in late January by The Washington Post, 59 percent of African Americans in Prince George’s said they oppose same-sex marriage, and 36 percent of them said they believe such marriages should be legal. Statewide, 53 percent of them were opposed, the poll showed.

Last year, Coates remained silent as the predominantly African American Prince George’s legislative delegation in Annapolis, pressured by many influential and large African American churches, provided crucial opposition that helped to scuttle the same-sex marriage bill.

Coates declined to discuss his own views of homosexuality. That, he said, would detract from what he sees as the real issue. “It is not a question of private belief,” he said, “but whether all citizens of this state have the same rights.”

To opponents, though, the matter of belief is exactly the issue. They say the Bible clearly teaches that homosexuality is a sin and that they are standing up for their religious beliefs. Their criticism of Coates’s stance has been loud and swift.

At the Friday hearing in Annapolis, Del. Emmett C. Burns Jr. (D-Baltimore County), an African American lawmaker opposed to same-sex marriage, wondered aloud what Gov. Martin O’Malley (D) might have promised Coates and the other African American minister from Baltimore who spoke up for gay rights. Over the weekend, Coates also received phone calls and text messages from black ministers questioning his position.

Pastor Ralph Martino of First Church of Christ in the District urged listeners of a local gospel radio station to visit Coates’s church to voice their disapproval. Coates said he realizes that some of his own members may disagree with the stance he has taken, but there has been little negative response from them.

After his first appearance with O’Malley on the issue at a press conference in late January, Coates took in more new members than usual for the three Sunday services beginning at 7:30 a.m. through about 1 p.m.

“It was our best Sunday in eight years,” said Coates, who has helped transform Mount Ennon from a small rural congregation into a bustling complex on Piscataway Road with parking lots bigger than football fields.

Coates said he was relieved but not particularly surprised. “The people in the pew,” he said, “are further along on this issue than those of us in the pulpit.”

Prince George’s County Council member Mel Franklin (D-Upper Marlboro), a member of the congregation, said that he, like many others, thinks marriage is a union between a man and a woman. But he said Coates’s position had not ruffled members. “I haven’t heard anything,” Franklin said last week.

For Coates, a Richmond native who holds a doctorate from Columbia University and also studied at Morehouse College and Harvard University, the decision to back same-sex marriage legislation is grounded in theology and civil law. He said that those who claim the Bible abhors homosexuality are misreading the text. Instead, he said, his study of theology and the Bible in original, ancient languages suggests that sexual abuse, violence and exploitation are being condemned.

But regardless of what people believe, he said, the issue is that gay partners should have the same civil liberties afforded all Maryland residents, such as the legal right to visit an ailing spouse in the hospital or pass along property.

“While the theological debate is an important one, it is for a different arena; namely, the pulpit, the seminary, the dinner table,” he said.

Supporting same-sex marriage will not compel religious organizations to perform such unions and will not interfere with the practice of religion, he said. To let the bill die again this year, he said, would create a troubling convergence of church and state.

“I think that using private, religious beliefs and local church practices for legislation establishes a dangerous precedent in America,” he said. “We have fought for inclusion, for freedom of religion, so that means if I want to be free to exercise my own religious beliefs, I have to extend that same courtesy and right to others, regardless of what I may think they do in private.”

Besides, Coates, said, the same-sex marriage debate is a distraction from more pressing issues: unemployment, lack of affordable housing, transportation and health care.

Joining public debate over a controversial issue is not new for Coates, who several years ago launched the “Enough is Enough” campaign against what he said were demeaning lyrics and images in music that degraded women and minorities.

A father of four children, Coates and his wife, Yolanda, an attorney, moved to Clinton in 2004. Previously, Coates, while earning his doctorate from Columbia, worked as a minister in Newark and became affiliated with Al Sharpton, who recently made a video for Marylanders for Marriage Equality supporting same-sex marriage.

Coates said he hopes his decision to encourage discussion about gay rights will help his congregation end what he called a tradition of “don’t ask, don’t tell” in the black community. And while he has no plans to perform same-sex marriages at his church, he said those who disdain gays and lesbians are ignoring the world around them.

“Gays and lesbians are part of our communities, they are part of our families, they are part of our church families,” he said. “I believe that the church ought to be a place where all people, regardless of their lifestyle, ought to be welcome.”