I've always thought laws like that - no sodomy, no gay marriage, no abortion period, and any other law that tries to use religion or whatever to deny someone their rights were foolish. Literally, None of these things hurt society. I can even understand the ban on some drugs that do cause dangerous consequences - but this is someone deciding to profess their love for someone else, to have sex, or to abort a child. I don't believe babies should be aborted after they can feel the pain, but that is out of care of an innocent life who knows nothing of the circumstance and not because I don't believe women shouldn't be allowed to abort.
Seriously though, the only justification for such laws is to try and enforce your own beliefs - and it kind of erases part of the whole separation of church and state principle. Not to mention, making laws against "sins" one group finds worthy of being banned, but conveniently forgetting laws against other sins such as, say, the mass consumption of alcohol, just makes people in favor of those laws seem like they're trying to create a society for their own benefit and half ass masking it with religion.
Have a nice day!