The EN13537 ratings assume a difference of 9*F between the "standard" woman and the "standard" man. Whatever that is.

I prefer to use the term "cold sleepers" and "warm sleepers," although the "cold sleepers" I know definitely include more women than men.

There's an age factor, too--our "thermostats" don't function as well as we get older. Fitness is also an issue.

I bought a Marmot Hydrogen (rated at 32*F) some years back, figuring that with my insulating clothing on inside I could get it down to the low 20's F. Ha ha. I started getting cold in it at the upper 30's F. By the time it got down to 28*F, I was shivering with all my clothing (including rain gear) on inside. This bag is now EN13537 rated, and I notice the "comfort" rating (women/cold sleepers) is 39*F. Evidently I'm not that far off the dummy measurement for women! (Make of that what you will. :D)