What's this swapping between men and women for temperature ratings? If there's a real difference (= ratings from experimental evidence) between men and women's experience in the same bag they should provide 'his n hers' ratings. If women do sleep warmer / colder in general it's not much help to me. Having said that, none of the rating on bags are that much help. I much to prefer to 'feel the cloth' as they say and make my own assessment.

How cold you can get in a bag without suffering some sort of consequence does seem to what the marketing people zero in on. It's as if the cold rating is some kind of macho statement where the better you buy the more it reflects on your status - "minus 20C, ha, you didn't buy one of those did you. They must have seen you coming. You'll freeze to death at festivals in that. Look at this one, this is what you should've got but I suppose budget was the problem. Rated -25C and stuffed full of the best quality goose down. Feel that quality; go on, feel it, rub it between your fingers, pat that padding, see how thick it is. That's what proper insulation feels like, not like those wafer thin cheap feathers shoved into your bag. Chicken's probably still running round somewhere looking for them".

What's never mentioned and rarely taken into account is how they cope in warm weather. Dump full length zips, build in a box foot and a mummy style head surround and you can get a few more degrees of cold rating for your marketing but it makes the bag almost unusable in warm weather. I'd much rather have a long zip so the bag can be opened out and used like a throwover when it's warm. The zip might make for a cold spot at the bag's limits but I'll trade that happily for some warm weather versatility. For the last couple of long bike trips we've dumped sleeping bags altogether and used domestic down filled duvets. A couple of them came secondhand from places like Craigslist and cost next to nothing.