Here's an interesting fact about sexual dimorphism: On average, if you were born a male, your hands are a little bit different from those of someone who was born a female. Most men have a pointer finger that is a little bit shorter than their ring finger. Most women have a pointer finger that's about the same length as their ring finger, if not a little longer.
People have noted this differences between the sexes for centuries. But what's it mean? Truth is, we really aren't sure yet. But it is correlated to a lot of awfully interesting things. In fact, some scientists think "the finger thing" (as I like to call it) is a hallmark of prenatal hormone exposure. Because of that, in the scientific literature, you'll find lots of examples of studies that try to find a connection between the finger thing and seemingly disparate traits, such as sexual orientation and gender expression.
We talked about the finger thing on a recent episode of the Sex is Fun podcast—what it's all about, what fingers could be telling us about people, and why it's maybe all just a bunch of hooey. Take a listen!
Also, for the record: My right hand has lady fingers. My left hand does not. How about you?
Maggie Koerth-Baker is the science editor at BoingBoing.net. She writes a monthly column for The New York Times Magazine and is the author of Before the Lights Go Out, a book about electricity, infrastructure, and the future of energy. You can find Maggie on Twitter and Facebook.