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To understand how Danny Stewart, Peter Mercurio and their son Kevin became a family of three, you have to go back 12 years to the 14th Street A/C/E subway station in Chelsea.

"As I was leaving the subway, I glanced over to my left and thought I saw a doll," recounted Stewart. "I continued up the stairs because I didn't think anything of it, but I glanced back at the floor and I saw legs moving."

Stewart quickly discovered it was no doll, but a newborn baby bundled up in a sweatshirt, his umbilical cord still attached. After calling 911, Stewart's next call was to his partner.

"Danny is a really calm person so when he called me frantic, I knew something was wrong," said Mercurio. "I literally felt his heart beat through the line and the panic in his voice."

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By the time Mercurio reached the subway station, the NYPD had already responded. Police named the baby Daniel "ACE" Doe, because it was Danny who found him at the A-C-E train station. A citywide search began for the baby's mother, covered by local news stations including NBC 4 New York.

Three months later, no one had come forward and Stewart found himself at a family court hearing. As he explained to the judge how he found the baby, the judge suddenly asked him if he would be interesting in adopting the baby.

"I think everyone in the court room, their jaws dropped, everyone was quiet," said Stewart. "Everyone was looking at me, and I said, 'Yes, but it's not that easy.' And she said, 'Well, it can be.'"

Stewart and Mercurio had only been dating for three years, and they had not discussed having a family. Gay marriage wasn't legal then, either, so they weren't married. But Stewart said at that moment, he just knew the right thing to do.

"I thought, 'Maybe this is destiny, maybe this is divine intervention. This is a gift we're given and how can we say no to a gift?'" said Stewart.

At first, the couple thought they would have months to prepare for the baby's arrival because of the mountain of bureaucracy and paperwork they had to go through, but the judge surprised them once again. A week after the initial court hearing, and three days before Christmas, the judge asked them if they would like to care for him for the holiday weekend.

"And he's been with us ever since," said Mercurio. "It was the best Christmas present ever. It was amazing."

They named the baby Kevin and eventually became his official adoptive parents. Kevin is now 12 years old and almost as tall as his dads. His parents want to protect his privacy, so NBC 4 New York did not interview the boy on camera, but off camera, the boy said he could not imagine what his life would be like if his fathers had not found him. It's something his parents often think about as well.

"It's something that's changed our lives forever, and we're better people for it, said Mercurio. "And we love him to death."

"I can't imagine life without him," said Stewart.