Did the Nazis Enact a 'Gay Genocide'?

That gays were rounded up is clear, but how serious were the efforts? Is it possible, is it legitimate, to speak of a "gay genocide" under the Nazis before and during World War II? There's no debating that the Nazis rounded up and killed a number of people for being gay, but does this make it a "genocide" in the same sense that their program to exterminate the Jews clearly was (as well as the Roma people and other ethnic minorities)? The question becomes, what is meant by a "genocide" as opposed to another type of crime against humanity, such as a massacre or state terrorism? Is it a matter of sheer numbers? Is it a question of intent, as some have argued, a concerted effort to wipe out an entire ethnic group? Is it the scope of the violence, or the level of involvement of the aggressor?