Yeah, now if only we could have a drug that turned everyone Caucasian, or Aryan... White skinned, blue eyed, blond haired...
...Oh wait, we kinda tried that before did we? And we had this big "war" thing over it. Cause of how extremely wrong it was to try to change what other people are, their identity, for absolutely no reason but personal taste? Funny how quickly we forgot that...
On a more serious note, I'm very much against this simply because it'll become a social scapegoat. "Yeah, see, we're ok to hate the gays now! They're choosing to be gay! they could stop being gay and take the damn drug! Nevermind that the very idea of asking anyone else to do this would be utterly appalling!".
And why would a gay person actually want to stop being gay for any reason other than to avoid social stigma? This isn't even like a visual change. Changing people's skin color could potentially have a merely cosmetic and non-discriminatory reason for being, you know. You could potentially want to change your skin color simply due to aesthetic reasons. Not because you're ashamed of your heritage, or to avoid social stigma, but much in the same manner you use a different suit. This doesn't really work with your sexual orientation. Why would you change what you like? "I want to change my sexual orientation because I like something else!". No you don't, otherwise that WOULD be your sexual orientation.
I could see something like this maybe being worth debating whenever we live in a world where gay people aren't considered "subhuman" and "defective" because they had the misfortune of liking something the majority doesn't. Today? No. I have a hard time seeing any reason for this research other than the same very misguided reasons that fueled the likes of Joseph Mengeles' research.