There's nothing wrong with gay characters. People didn't like Storm or Black Lightening when they first came out. They didn't like the idea of a "Negro" as a superhero. Same thing. Faster acceptance. It's inevitable.
How is a homosexual? Unless he comes out or we see him in bed with somebody... or wait he's not gay. He doesn't have human needs. He doesn't require food, water, air, or sex for that matter. No to mention the guy is the biggest loner in the Marvel Universe. He's asexual.
Actually, you're right. The Black Cat is bi-sexual. In Spider Girl #45-47 it is plainly revealed that she has a lesbian lover by the name of Diana. Many folks said this couldn't be true because it was in actuality an alternate timeline, but in the Spider-Man/Black Cat Mini-series, The Black Cat specifically says that it's been along time since she's had a boyfriend or a girlfriend.
The truth is that there's a huge list of gay characters in comics... A few of note are:
Northstar (Marvel)
Apollo & The Midnighter (Wildstorm)
Destroyer and Union Jack II (Marvel)
The Black Cat (Marvel)
Destiny and Mystique (Marvel)
Moondragon & Phyla (Marvel)
John Constantine (Vertigo)
Mephisto (Marvel)
Starman III (DC)
Just for a few examples.... Not sure why the sudden surge in gay characters, but being an African American heterosexual male, I can say it does take me back to the days when suddenly everybody wanted to have a black hero. Gay people, just thank God they're not putting "Gay" in your hero's code names like they did with the word "black".
She has a baby with superman in the 'the kingdom' elseworlds miniseries (set in an alternate future timeline).
The 'Red Son' wonderwoman also is hot for superman
And for the record on the Silver Surfer... he, himself is not gay, though he is the reason Mephisto is listed as bisexual. Mephisto once turned himself into a woman to try to seduce the SS, but the SS wasn't having it.... wait a sec... the SS wouldn't get with a nice voluptuous woman trying to seduce him? Maybe he is.... naw.... he's not gay.