I hate this expression. I heard it for the first time in ages this morning - someone in my office had on a commercial radio station with some kind of competition tying in with the launch of some sort of new film which involved a 'battle of the sexes' where I presume a man and a woman competed against each other for a prize.
But anyway, I've always found the concept slightly odd. A lot of people (mostly women I'd argue if I were making sweeping generalisations) seem to perceive this rivalry between men and women that I've never really quite followed. For example, occasionally you see women in TV gameshows/reality shows talking about how they want to win to "strike a blow for the girls". But clearly no-one represents their entire gender and they're just striking a blow for themselves.
So anyway do you believe in thsi kind of stuff? If you saw a man and a woman in a competition would you automatically root for the one of your own gender or do you think it's all a bit of nonsense?