Dr. Marc Breedlove

I couldn't think of any way to explain that except that, well, the lesbian might have been exposed to more prenatal testosterone than straight women before birth.

And I don't know how to explain that except to say, well, maybe prenatal testosterone, maybe if you're exposed to that before birth, you're more likely to be attracted to women when you grow up.

Which, oh, well, that might explain why 95% of men are attracted to women, right?

Because they're all exposed to prenatal testosterone.

So this oddball study really gets me to thinking that maybe there's, you know, something to that.

But...

But I'll forget it.

I'm still working with my rats and paramiscus and Siberian hamsters and stuff.

I'm happily doing that.

And then – and I remember it so well.

In 1999, I'm in my office at Berkeley and I read this paper that says there's a sex difference in the ratio of fingers that's present in nine-year-old children.

What?

I've studied sex differences my whole adult life.

How do I not know about this?

And it turns out that if you measure the length of the second digit... The pointer finger.

Right.

And the length of the ring finger.

And you can do a simple ratio.

Divide the length of the second digit by the fourth digit, so-called 2D-4D ratio.

And a guy named John Manning was reporting that there's a sex difference there, that it's...