i'll preface my comments with the acknowledgement that I know a number of women who can drop mel ike a rock on a climb. That being said, I've observed the same thing has Sincity on a fair number of occassions. It's simply a power to weight ratio thing. They may be lighter, but have less power too. Lots of people can hang in the pack, but on the hills it comes down to power to weight ratio, so it's not unusual to get women on a fast group ride that are strong enough to hang on the flats but not on the hills. Of course you get men like that too.