There were probably some primate ancestors of ourselves that as soon as they saw children they thought, how delicious, what a source of fat and protein, and ate them all up.

The genes that motivated them to do that did not prosper as much as the genes that motivated our other primate ancestors to say, how adorable, I will love them and protect them.

Now that we're reflective beings, that we can think about what we do, we could choose for instance to have sex without the idea of having kids.

We have this flexibility.

And then the question of why people choose to have kids becomes more complicated.

The negatives of having children are obvious.

You don't need a psychologist to tell you about them.

Money, anxiety, sleepless nights, sleep deprivation, all the time they take up.

Studies find that for couples who have kids, the number one source of fighting and argument and tension, it's not relatives, it's not sex, it's not money, it's kids.

It's a really hard question from a hedonic point of view.

Are children a positive, a negative?

And I think the answer's going to differ from person to person in perhaps unpredictable ways.

But people don't seem to say, wow, what a disaster that was, what a bad move.

And I think if you tell parents, you know, there's a lot of evidence saying that kids don't make you overall happier.

Their response will often be, that's not why I have kids.

That's not why I love my kids.

And I think the reason goes back to the idea of motivational pluralism.

So motivational pluralism is the fact that humans want many things.

We want pleasure.

We want to be good.

We want meaning.

We want purpose.

So if you ask parents whether their lives are meaningful, they tend to say yes more than non-parents.

Meaning, in the broad sense, is intimately related to the more heavy duty, suffering and difficulty.

So Danny Kahnleman talks about two different kinds of happiness.

One is experienced happiness, which is, you know, you're doing something and I tap you on the shoulder and say, how happy are you?

How's it going?

The other one is remembered happiness.

Remember when you were doing that thing, how much did you like it?

The experienced happiness with children is complicated and often lower than you would expect, while a remembered happiness could be higher.

One explanation for this proposed by Jennifer Senior, who's a science writer, has written a lot about this, is that our memories are distorted in interesting ways.

And we often remember the peaks.

We remember the good times.

I think back on having my kids and I have a million memories of these wonderful things, which I go back to over and over again and kind of nurture.

So my remembered happiness might be high.

The experienced happiness, the day-to-day stuff, the million diaper changes and getting up in the middle of the night, you just forget all that.

If somebody asked me, do you recommend I have a kid or not?

I would say, hey, this is a tough call, but what I would advise is explore what it is to have a kid.

Look at some of the research into how people describe their lives.

Talk to parents, not with an eye towards saying, oh, plainly this is a good decision or plainly this is a bad decision because the data is not going to be there.

It's just too mixed.

What you could find is how well it meshes with how you are or how you want to be.

Having children is what my friend and colleague, the philosopher Laurie Paul, calls a transformative experience.

It's the kind of experience that changes you in such a way that right now you can't project what it would be like to be a parent because when you are a parent, you'll be a different kind of person than you are now.

You have different priorities, different interests, different drives, different experiences.

Now, I'll add a caveat, which is there's other ways to get meaning in life.

Some people I love very much are non-parents either due to circumstance or due to choice, and they live very rich and fulfilling lives.

There's more than one route to meaning, but I do want to suggest that that's one reason, one argument.

Forget about populating the universe.

Forget about perpetrating the species.

One argument in favor of having kids is that not that it scratches the itch of happiness, but that it's part and parcel of a meaningful life.