Some (well, all really, but still) of the arguments against were ludicrous.
One MP, Stephen Timms, stating that marriage is for the purpose of children alone, only to have a Labour colleague, whose wedding he attended, point out she married long after there would be any chance of kids, thus suggesting her marriage was invalid, was absolutely farcical. As was his response - 'I'm talking about hundreds of years ago'. Er...?
**** idiots.
Not that this matters of course - the Lords won't let this fly and Cameron's not daft enough to invoke the Parliament Act.