Miami composer Desmond Child had one of his biggest hits with Ricky Martin’s 1999 worldwide smash, Livin’ la Vida Loca. Now nearly 60, Child’s personal life has become anything but.

He and Curtis Shaw, partners for 24 years, live in suburban Nashville where they’re raising twin sons, born almost 11 years ago at Mount Sinai Medical Center in Miami Beach. The boys are the subject of a new documentary, TWO: The Story of Roman and Nyro, which premieres Tuesday at the 15th annual Miami Gay & Lesbian Film Festival.

“Why did we do it?” Child asks rhetorically about authorizing such a personal film. “We felt it was a way we could help straight people understand — and have gay people see that it is possible — that they could live and be parents and have that kind of joy in their lives.”

Child and Shaw had been together about a dozen years when they decided to start a family.

“I had been watching the news,” Child recalls. “George Bush was trying to kill the gay marriages and what not. He went on TV and says, ‘I don’t know why they want to get married. They can’t have children.’

“Well, people who are infertile still want to get married. Should that bar them from getting married? We’re not infertile. We can have children. We are having children. There are thousands of children being born biologically to gay parents. It’s not just about adopting.”

The same argument could be heard in March during gay-marriage hearings before the U.S. Supreme Court, says Child, 59. “Why don’t they stop talking about procreation? We’re procreating! End of discussion America!”

Born in Gainesville and raised in Miami Beach, Child has been out of the closet since 1979, when his band at the time, Desmond Child & Rouge, released its second album, Runners in the Night. One track, The Truth Comes Out, “was my exuberant coming-out song,” he says.

He soon shifted from performing to composing, and has written and produced huge hits for Martin, Bon Jovi ( Livin’ on a Prayer), Cher ( We All Sleep Alone) and Joan Jett ( I Hate Myself for Loving You).

In 1989, Child met Shaw, then an aspiring actor from Columbia, Mo., working as a maitre d’ in a New York City restaurant. Soon a couple, they moved to California and later Miami Beach. They broke up in the late ’90s, reuniting a year later.

“After the reconciliation, we said, ‘Let’s do this, let’s have the family we always wanted,’ ” Child recalls.

They worked with Miami Beach family lawyer Elizabeth Schwartz and Growing Generations, a Los Angeles company that helps gay men become parents.

The son of Cuban singer Elena Casals, who died last year, Child says he himself came from “an alternative family.” At 18, he learned that his biological father was not the man married to his mother when he was born in 1953.

It was “very important to me to have my own biological children,” he says.

Shaw, one of four sons of a conservative Christian mother and a school-superintendent father, says a biological connection didn’t matter to him.

“I just knew before it even happened, before we became parents, it wouldn’t make any difference. I would love the child and he would love me,” says Shaw, who adopted the boys in California and has been their stay-at-home dad.