Yesterday, it emerged that one particular scene will be cut from the show when it airs in the UK, although it will be broadcast in the US on cable network Starz.
A BBC spokesperson confirmed the news and claimed that the cuts "do not change the story in any way".
However, speaking before the controversy, Barrowman claimed that the intimate moments in the show are part of the plot.
"It's not gratuitous sex," he told Zap2It. "It facilitates the story, so it's nothing they grab just to put on the camera and sensationalise it."
Barrowman also revealed that fans will find out more about Jack's romantic history, saying: "You go back into history with Jack and you discover an integral relationship that is part and parcel to what is happening.
"It's a massive story about his past and probably, if I can say this, one of his true loves. So there are relationships, but there are also some one-night stands... some dirty."
Barrowman previously joked that Jack has "full-on boy sex" in the show.
Torchwood: Miracle Day airs on Fridays at 10pm on Starz in the US and on Thursdays at 9pm on BBC One in the UK.
Watch John Barrowman talking to Digital Spy about Torchwood below: