(L-R) O.J. Simpson and his father. ESPN One of the big themes in the ESPN documentary "O.J.: Made In America" is the awful abuse O.J. Simpson subjected his wife Nicole Brown Simpson to prior to her murder — both physical and otherwise.

It's possible that violence may have stemmed, at least in part, from Simpson's relationship with his father.

In part one of the docuseries (airing on ESPN now and available on the Watch ESPN app), we learn through a childhood friend of O.J. Simpson's that the former football star's father was gay.

It was something the "Made in America" director, Ezra Edelman, didn't even know if he could get anyone in the film to talk about. But surprisingly, the topic came up quickly through the friend.

"Calvin [Tennyson] was my first interview for the movie, it was back in October of 2014," Edelman told Business Insider recently. "I didn't know that he knew [O.J.'s father was gay], it wasn't something O.J. talked about. But he brought it up and told a story about [O.J.'s] father very organically."

The story is a recollection Tennyson had of seeing Simpson's father in his apartment in San Francisco, wearing only a bathrobe and standing next to another man in the room, who was also just wearing a bathrobe.

Simpson rarely spoke about his father. But in part two of "Made in America," the topic of his father's homosexuality comes up again during a harrowing story.

According to a friend of Simpson's, O.J. "freaked out" at Nicole for allowing their son to sit next to a gay man at a restaurant. The friend then got a call the next day notifying him that Simpson beat up Nicole the previous night, New Year's Eve, 1989.

Looking for guidance, Nicole went to Ron Shipp, a Simpson friend and LAPD officer who taught domestic-violence classes.

Nicole asked Shipp, according to Shipp, if Simpson beat her because his father was gay.

Shipp answered, "I don't know, but a lot of it has to do with their self-esteem."

Simpson's father died of AIDS in 1985.