I just want to point out that usually when a female person hands me a jar to open, they've already done a lot of the work of loosening it almost to the point of it opening.
That being said, there's two things men have that make them better jar-openers, in addition to a head start:
1) Bigger hands, on average. Yes, hand size varies widely, but I can certainly understand women who prefer men with big hands. That makes perfect sense.
2) Much lower concern with pain. Often, in the course of doing chores or household repairs, men will hurt themselves. Indeed, I pretty much always used to burn myself really good when, for instance, changing the oil on the car. (It changes better hot, you see.) Or I'd be changing a spark plug or something, and then go inside and have a beer, and have someone say, "sheesh, man, you're bleeding all over the place," and I'd notice it and go, "Oh, is that what that is?"
Sometimes when I open a jar, either my hand cramps, or I get a kind of indian-burn thing going from the texture of the lid bruising (for want of better word) my skin. It might last, oh, an hour or two. Point is, many men are stupid enough to do stuff like this even though they know it's going to hurt. They just don't care very much.
In addition to the jar opening tricks listen below, though, I'd always keep around a rubber jar opening disk, and, for the truly horrid jars, the special jar-gripping pliers my Mom has. The best picture on the web I can find on short notice is here:http://www.emsdiasum.com/microscopy/products/safety/laboratory.aspx?mm=20
I wish I could find one now.
The thing has two teeth on either end. The teeth bite into the lid pretty hard, providing both good traction and, hopefully, enough deformation to break a vaccuum seal. I think these pliers can also crack a glass jar in half, which is a pretty good way of teaching it a lesson if it's really incorrigible.