Quinto said playing Louis Ironson, who ditches his AIDS-stricken boyfriend in the play, was a challenging and rewarding role that also reminded him that gay rights is still an evolving issue.
"As a gay man, it made me feel like there's still so much work to be done, and there's still so many things that need to be looked at and addressed," he told New York magazine.
People magazine said Sunday the interview marked the first time Quinto had publicly discussed his sexual orientation.
Quinto pointed to the flap over homosexual marriage and incidents of bullying as examples of the disparity. "There's a hopelessness that surrounds it," he said.