Why are so many gay people Liberal?

What is it about being gay that makes someone liberal? I understand the "conception" that conservatives are all anti gay who would apparently ride thru gay neigh boor hoods in white cloaks killing gays if not for Democrats. But what is it about their policies that you like so much? Are the vast majority really all pro-choice, pro big govt or do you think because you agree with the social policies that you should support the fiscal policies. Are there any gay Libertarians?