His decision to postpone transitioning was a difficult one, and Kearns experienced mental anguish during the pregnancy, being in a body that felt wrong for him.

"I was really concerned for AJ whilst he was pregnant because I knew he had such strong dysphoria and that it caused a lot of anguish," said White. "But somehow he found the inner strength."

But despite the pain of pregnancy, the moment of birth was beautiful, said Kearns.

"I feel privileged to create a life," Kearns said. "Anyone that gives birth to a person will be a witness to the fact that it's a miracle."

"First meeting Luka when she was born, as any parent will tell you, is the greatest joy in the entire world."

Kearns said his pregnancy challenged preconceptions of what it means to be a man.

"I had the capacity to bear a child and I am a man, and that would be very confronting to a lot of people," he said.

But although some people might find the idea of a dad having a baby strange, psychiatrist Fintan Harte said there is "no reason" Kearns should not have given birth to Luka.

"Children have rich fantasy lives — frogs turn into princesses, pumpkins turn into coaches, and a woman turning into a man and vice versa is literally child's play," he said.