Hello and welcome to Deeply Human, the show about why you do what you do.

It's general admission, so sit anywhere you like, but if you sit on top of someone else,

you must have their express consent. I'm your host, Dessa, and I've got an unusually sexy program

queued up this time around, so if you are in the company of pint-sized listeners who don't yet know how they got made, this program might let the reproductive cat out of the bag.

Today, we're tackling the question, why do you have sex all the time?

Now, those of you who are seated alone may be thinking,

lady, you are mistaken because I am definitely not having sex all the time. And those of you

sitting with a date might be thinking that's obvious. We have sex because it feels good. But I

assure you that is only half the story. You are in for an evening of evolution, wonder, and Victorian perversions.

We're about to find out why humans have sex at times that our fellow mammals don't.

Let the show begin.

My name is Steve Gangstead.

I am a professor of psychology at the University of New Mexico.

And I study sex.

I study sexual interest.

I study hormonal influences on sex.

Perfect.

I'm interested in sex.

Okay.

To understand the quirks of human sex,

we first need to know how it works for most mammals.

Here's Steve, giving us the lay of the land.

...