I've found most same sex marriage supporters don't like to think about this subject. They prefer to feel they are good people who sympathize with gays and want same sex marriage because it feels good to support equal 'rights'. The thing is; homosexuals have equal rights under the same laws as everyone else. Homosexuals have always married, Oscar Wilde and Meredith Baxter are two examples. What would happen to married homosexuals if same sex marriage becomes law? Would that change encourage them to divorce? Would they sue their spouse for custody and tell the court the child's mother is a single parent and they have a same sex marriage so they should have custody? Would courts find in sympathy with a mascot victim group because they want to make up for past inequity?It should not hurt to think, maybe you should stop thinking.
Once you stop making decisions based on your feelings and think about the consequences of a policy, you stop being a liberal and become a conservative.