As a woman and a cold sleeper, I've found the EN 13537 "comfort" ratings to be right on. In both my WM Ultralite and the Marmot Hydrogen I once had, the "comfort" temperature is the approximate point at which I have to start adding warm clothing inside my bag. The "lower limit" rating, for me, is the approximate point I start to shiver even when wearing all my insulating clothing plus a vapor barrier. (That assumes an adequate sleeping pad, not the regular NeoAir!) I still don't know why they have the "extreme" rating; I'd be dead long before it got that cold!

TomD is right, Marmot uses the EN ratings properly, showing all three ratings.

What is individual is each person's true comfort level within these ratings! A warm sleeper (regardless of sex) may be just fine with "lower limit." A cold sleeper (regardless of sex) is better off with "comfort."