He has been with his girlfriend, Silvia Meichel for almost a decade, so it appears he is heterosexual.
He does believe in gay rights and recommends that gay football players should come out of the closet. He could just as well defend a friend who is gay...
(From his Wikipedia page) "He [Gomez] also would like a 'radical rethink' about homosexuality in football."
Yes, he is!! At least, according to anecdotal sources. A friend of mine who is journalist, has told me that she had an interview with Mario, and while they talked, his boyfriend called him.
The character of Flapjack is not written with sexual orientation
Nothing is known of her sexual orientation.
The Joker's sexual orientation is not written into his character.
Soko's sexual orientation is heterosexual/straight.
The fictional character of Yoshi is not depicted with sexual orientation.
The sexual orientation of David Rodriguez is unknown.
Matt Evers' sexual orientation is not known.
The SNL character "Gilly" was not written with sexual orientation.
Frankie Muniz has not stated his sexual orientation.
Reginald VelJohnson has not publicly spoken about his sexual orientation.
I think you mistake "sexual orientation" with specific types of orientation. Sexual orientation is a part of every humans make up. A person can not have a sexual orientation. Your sexual orientation is what makes you gay, straight or bisexual. Homosexuality IS illegal in some countries. You can outlaw a behavior but you can't outlaw an urge or feeling.