That tactic by those against marriage equality is nothing new. Go back in US history and one of the arguments against abolishing slavery and civil rights was “Those negroes are going to take your women if we free them or give them rights!” And, of course, in the 1960s, bans on interracial marriage were struck down by the Supreme Court, and that is good!
Go back and you’ll see “No, we can’t let women vote! If we do, next they’ll be independent!” And, of course, many are now, and that’s good.
Interracial marriage and adult women NOT having to be subservient to a husband, father, or brother seemed radical and jarring, but what more people should have asked at the time was, “What’s wrong with that?”
So let’s do that now when it comes to adult relationships and marriage. What’s the problem with letting consenting adults be together the way they want? Challenge the prejudiced. They won’t have a good answer. They’ll scoff, or jump up and down, or point and say “See!!!” But those aren’t arguments. They don’t explain why we should discriminate against any consensual relationships between adults.
My call to solidarity: http://fullmarriageequality.tumblr.com/FME