Birdo, according to official Nintendo lore, is male.
The reception to the article has been largely negative. (I'll spare you the tweets, but it's broadly variations on "Really?") I think people are overreacting a bit, but that the overreaction comes largely from the right place: gamers don't really want to deal with gross characterizations of gay culture. (DeVries' comment about gay folk not getting sports references particularly grates.)
Yet a larger question looms: Why aren't there more gay video game heroes?
I wracked my brain to think of openly gay heroes. Not just gay characters-which while not uncommon, seem to be predominately flamboyant, evil, or giggling lesbian stereotypes—but central protagonists. The only characters that sprang to mind are the heroes of BioWare's role—playing games like Dragon Age and Mass Effect, who can be gay depending on what choices the player makes. Better than nothing, certainly, but not the same as a character who is simply gay, no player interaction required. (The case is a little better with supporting characters.)
The explanation could be as simple as why there are few unassailably gay heroes in Hollywood movies: more commercial endeavours than artistic ones, any deviation from the perceived norm that would keep people from spending their money on a game gets sanded away.
Perhaps we shouldn't be so quick to ignore the discovery that DeVries has made about Yoshi and Birdo just because it was presented in such a ham-fisted, lazy way. (Although he's hardly the first to notice that Birdo is queer.)
That one of Nintendo's major characters has openly dated a transgendered character is a hilariously small step, but at least it's in the right direction, especially if Nintendo confirms the official 2003 reference to Birdo ("Catherine" in the Japanese version, but still male) as Yoshi's "boyfriend".