I'm assuming those are dudes? Or am I missing out on something else pertinent to the joke?
Also, a fun legal FYI for you. As far as I know, Alabama is the only state which allows you to change your gender legally if you have a sex change. I assume they require a full genitalia sex change; I haven't done any research on it. This was brought to my attention by my Conflict of Laws professor.
So, essentially, gay marriage could be legal in Alabama...if you'd still consider the couple as being the same gender after one of them acquires some surgical alterations.