Dr. Marc Breedlove

And to give you an idea of what that means, if I had you grab a sample of 1,000 people, and I'm going to tell you one thing about each one of them, and that's their height.

That's all.

And now I give you the job.

You've got to guess what sex they are.

And I can tell you what you want to do.

to maximize your hit rate.

Everyone who is five feet, five and a half, you're going to say those are men.

And if they're less than that, you're going to say they're women.

And you'll be right about 80% of the time, which means you'll be wrong almost 20% of the time, right?

And so everyone, you can see that there's some predictive power there, but it's far from perfect.

Well, this sex difference in digit ratios is half a standard deviation, so a quarter of that.

And so that means there's much more overlap.

And we know that other things influence digit ratios too, not just prenatal testosterone.

And so this is why there's no predictive value.

So anyone who looked at their hand while we were talking about this and got worried

I don't know anything about your particular prenatal testosterone level, no matter what your digit ratio is.

I mean, in those days, we didn't have enough people that identified as bisexual to

to have a reasonable sample.

And it's interesting, and that's something that's changed, right?

I mean, if you do surveys now, especially among younger people, there are more people who report that they are bisexual than there were then.