In this modern world, it gets tougher and tougher to figure out if someone is a Jim or a Jane. Whatever happened to the easy era of codpieces and corsets? Without those to fall back on, here’s a bit of physics you can use to figure it out in a pinch.

Have the person in question fold a small piece of paper into a little tent. Kneel on the floor and put the paper between their fingers, as in prayer, with their hands at their forehead. Have them bend forward at the waist and place the paper in front of them on the floor, and sit back up. Now, they should put their hands behind their back, and lean forward and try to touch the paper with their nose, while keeping their balance.

If they fall forward, it’s a man. If they keep their balance, it’s a woman. (Note, this doesn’t always work, choose your test subjects carefully).

What’s going on? Women have a lower center of gravity, we’ve got short torsos, long legs, and those nice wide hips. So if you were able to balance a woman lengthwise on your arm, her balance point would be somewhere around her belly. Men, on the other hand, have long torsos and a lot of weight in their chests. So when he tries to lean forward to touch the paper, he can’t do it because it brings his center of mass too far forward in front of his knees and he falls over.

Another way to see this biological difference between men and woman is this. Find a man and woman of equal height and have them stand next to each other. Her legs will be longer than his, and his torso will be longer than hers It’s quite striking. Or, find a man who’s a bit taller than a woman. Chances are their legs will be of equal length!

And an insightful addendum from Swans on Tea

Add “Can I balance you lengthwise on my arm” to the list of “things likely to get me slapped”

I am a science education and communications consultant -- view my website for my full range of services.