While some kids probably grow up without any issues, I haven't read any studies that concretely state that children who are raised in a gay household develop without any psychological problems. LGBT community tends to point out anecdotal incidences as proof but there hasn't been any long term studies (AFAIK) to show what damage it could cause to a child. Thus I choose to veer on the side of caution.
Well, they're not really hard to find.
Wikipedia has a section on LGBT parenting with links to dozens of scientific studies and meta-analyses, and the peer-reviewed consensus over the past few decades has been that there is no substantive difference between gay and straight parents. But if you haven't read it, it must mean that the opposite is true...
Or, hey, let's get anecdotal. Did you know that nearly 100% of every terrorist, serial killer and mass murderer in the history of human civilization was raised by heterosexual or single parents? Some of the worst atrocities in human history were orchestrated by dictators born to heterosexual parents; Hitler, Stalin, Pol Pot, Mao, not one gay or lesbian parent in the bunch. Maybe the world needs more gay and lesbian parents to prevent these horrible atrocities from happening again...
Obviously that's a ludicrous argument. Just as ludicrous as your "I don't have any information, so I'm against it" when all the science disagrees with you. Choosing to remain ignorant is your right, and no one can take that away from you. Wearing that self-proclaimed ignorance as a badge of honor while claiming to be on the side of reason by "veering on the side of caution" in defiance of actual facts? That's asinine. You're welcome to your opinion, but don't try to rationalize your bigotry through a lack of awareness of what's been studied.