The day is observed on October 11 to support lesbian, gay, bisexual and transgender people.
The new Superman Jon Kent, the son of the first Superman Clark Kent and reporter Lois Lane, is bisexual. The development is part of DC Comics' latest series.
The young man kisses reporter Jay Nakamura in issue five of the comic book "Superman: Son of Kal-El." The book will be released on November 9.
Tom Taylor is the comic's writer. He told reporters with Reuters, "It's not a gimmick." A gimmick is a trick or device meant to gain attention.
Taylor wore clothes with a rainbow-colored Superman "S." He said that when he was offered the writing job, he thought there was a chance to offer readers something different.
"I thought, 'Well, if we're going to have a new Superman for the DC Universe, it feels like a missed opportunity to have another straight white savior," he said.
People have mostly supported the idea, Taylor said.
"People are saying for the first time ever they're seeing themselves in Superman - something they never thought was possible," he said.
The new Superman also cares about climate change and refugees.
Taylor said Jon Kent is "a very new hero finding his way, fighting things his father didn't as much."
I'm Caty Weaver.