Superman "is probably the most heterosexual character in any movie I've ever made, " said Bryan Singer, director of Superman Returns, a new movie about the crime-fighting superhero that opens on 28 June. "I don't think he's ever been gay."

In recent months, the movie's ability to lure its target audience has been questioned by internet gossip probing the superhero's sexuality.

Young men are the movie's target audience and the film needs to attract millions of them to earn a profit and relaunch the Superman film franchise.

A major gay magazine, The Advocate, ran a cover story with the headline: "How Gay is Superman, " and the Los Angeles Times weighed in with its own story on whether being gay might hinder or help the movie's box office receipts.

After all, gay romance Brokeback Mountain won awards and raked in $178 million ( 140 million) worldwide.

Singer said his version of the Man of Steel, who is played by Brandon Routh, is a "very romantic icon" . . . handsome, virtuous and vulnerable.

In the movie, Superman comes back to Earth after a five-year absence. Early on, audiences learn the love of his life, hardcharging reporter Lois Lane, has moved on from her infatuation with him. She has a new boyfriend and a child.

Yet when he re-enters her life, Lois still has that sexy gleam in her eye, and he can't wait to fly her to the moon.

"We were all scratching our heads, " said Paul Levitz, president and publisher of Superman owner DC Comics. "He's not a gay character."