In a new BBC program, The Making of Me, John Barrowman (pictured here at an unrelated appearance at G-A-Y nightclub in London) undergoes “a series of tests including a DNA examination that is compared with his straight brother's, and he takes to the streets of LA to try out a theory that the origin of homosexuality is linked to events in the womb that may affect the foetus.”

According to the network, “Throughout the programme, as well as picking up clues from psychologists and scientists, John also meets some celebrities and extraordinary people who help shed light on the origins of their traits.”

The Guardian reports: “The results of the programme – is it nature, is it nurture? – are a closely guarded secret, though Barrowman has always been convinced that sexuality is not a choice. ‘I've always known who I am,' he says. ‘That's what I believe. I feel I was born this way. I've never questioned that.'”…He mentions interviewing a Seventh Day Adventist ‘ex-gay' man while filming The Making Of Me, who believed that homosexuality was incompatible with a fulfilling life. ‘His idea was that you had to have the white picket fence and the farm and he was talking about it like it was something that I could never have,' says Barrowman. ‘And I actually said to him, ‘Yeah, but Ron, I have a partner, I have a dog, I have really nice cars, I have a beautiful home, I have a home by the sea and the beach. You can have that and be gay.' But he just couldn't see that.'”

But it was his contact with those who are questioning their sexuality that pushed him to do the show: “I have to put it this way. There are some days that I sign, like, 400 pictures, autographs and stuff. And among those I generally get a bunch of, say, four, five emails and some written letters from young men and women who are struggling to come out of the closet and they don't know who to turn to because they're afraid of their family's reaction and they're afraid of their community's reaction. So when they approached me to do this [The Making of Me], I thought, ‘Yeah, you know, I really kinda have to do it.' I do think I've got a responsibility to help change perceived attitudes or try to change them.”

The Making of Me airs July 24 in the UK on BBC1 from 9-10pm.