You used several adjectives with a normative tinge "enormous debt", "edge of solvency" and colorful imagery "precariously holding onto a rope above a pond full of crocodiles", which sound like they're designed to get the reaction "Oy My God! What has America (or pick your favorite country) come to?!", rather than the reaction "buying a house in an expensive area sounds risky".

I have no problem with your comment, and I'm glad to explain the reason why I made my original comment that way. The reason why I used such emotional imagery is that I wanted to depict the way people feel about their situation, which is the relevant thing in this context, even if the way they feel is unrealistic and biased. (Since the way they feel, and not some ideally objective evaluation of the situation, will ultimately determine their decisions about having kids.)

(By the way, do you really think that "enormous debt" and "edge of solvency" are not perfectly realistic descriptions of how many, if not most people in their child-bearing years live these days?)

On the object level topic, your argument seems very focused on debt, do you think renting a house in a similar area substantially lessens the burden?

I'm probably over-focusing on debt, since I myself consider any serious indebtedness with horror. I would guess that debt by itself is probably a much lesser source of worry to most people.

Now, when it comes to the issue of renting vs. buying, this is one of those things where people, including otherwise smart and successful people, tend to have opinions that seem seriously crazy to me. As far as I can tell, among the North American middle classes, it seems to be near-universal belief that a basic prerequisite for serious family life is owning a house, so the idea of renting is a non-starter. There is also the near-universal belief that renting is somehow a raw deal compared to buying, so that renting sends a strong signal that you're either stupid or, more likely, can't be approved for credit because of some shameful history you're hiding (and all the bad qualities it likely implies).

All this despite the fact that basic economics strongly suggests that renting should be a better deal for nearly everyone. (Unless perhaps the relevant markets are distorted to an enormous degree by subsidies, regulations, and perhaps also status signaling games, but in reality I see only the latter in sufficiently strong form.)

However, this gets us to the more general issue of various other expensive status games that one is supposed to play in order to be accepted among one's social group nowadays. This is a difficult and complicated topic, but on the whole, it seems to me that for a variety of reasons, these signaling requirements tend to expand as one's career and income advance, so in the end, it's difficult to avoid the situation where one is constantly walking on the edge financially. Needless to say, all this certainly isn't conductive to having kids.

At least in the US, there is a big subsidy for homeowning in that you can deduct the interest on you mortgage (I think this only applies to your first home ).

3juliawise8ySo it seems we all agree that your crocodile-pit description does not necessarily reflect reality.

Review: Selfish Reasons to Have More Kids

by jsalvatier 3 min read29th May 2012260 comments


This is a review of Bryan Caplan’s book Selfish Reasons to Have More Kids. Co-written with Walid.


Adoption studies indicate that differences in parenting styles have mostly small impacts on long term life outcomes of children, such as happiness, income, intelligence, health, etc.. This means that parents can put less effort into parenting without hurting their children’s futures. If you think kids are neat, then you should consider having more. 


Note: We think this is a pretty useful book, and it has changed our minds on how many children we want to have, though neither one us has any children yet. Also, neither of us are experts on twin or adoption studies.

Caplan argues that parents drastically overestimate their ability to improve the adult lives of their children. His argument is driven by adoption studies, which suggest that there is very little that parents can do beyond techniques employed by the average parent that would get them better results with their children. Specifically, the following areas are identified as areas where differences in parenting don’t seem to matter:

  • No effect on life expectancy, overall health (as measured by the presence/absence of particular health problems and self reported health), height, weight or dental health.
  • No effect on intelligence.
  • No effect on various measures of personality: conscientiousness, agreeableness or openness (not certain about extroversion or neuroticism).
  • Little or no effect on marriage, marriage satisfaction, divorce, or child bearing.

But that is not to say that styles outside of the average do not matter at all -- there are a few areas where parenting differences do seem to have an effect:

  • A small effect on adult drinking, smoking and drug problems.
  • A small effect on educational attainment, but no effect on grades in school or on income.
  • A large effect on political and religious labels, such as whether you call yourself democrat or republican or Christian or Muslim but small effects on actual political and religious attitudes or behavior.
  • A moderate effect on when girls start having sex (but not boys), but no effect on teen pregnancy or adult sexual behaviors. 
  • Possibly a small effect on sexual orientation.
  • A moderate effect on how children remember and perceive their parents.

So how do adoption studies lead to these conclusions?

Adoption studies (If you have a link to a better overview or discussion of adoption studies, we'd appreciate it) help find out the influence of parenting differences on adult outcomes by comparing adoptees to their adopting family. If adoptees systematically tend to be more like their adopting family than like other adoptees along some measure (say religiosity or income), that implies that parenting differences affect that measure.

When an adoption study finds that parenting does not affect outcome X, it does not mean that parenting cannot affect it, just that the parenting styles in the data set did not affect it.

The evidence Caplan talks about is primarily long run life outcomes. Shorter run life outcomes often do show larger effects from parenting, but these effects diminish as the time horizon increases.

If parenting doesn’t matter, what does?

Caplan references twin studies in showing that genetics have relatively big effects on all the measures previously mentioned. This explains why we see strong correlations between parents’ traits and children's’ traits. He specifically uses it to call out attributes that we would commonly ascribe to parenting, but may actually have a much larger genetic component.


Once Caplan has argued for the stylized fact that parenting has only small effects on major life outcomes, he explores some of its implications. 

Don’t be a tiger parent

One big implication is that you should put less effort into trying to make your kids into great adults and more effort into making your and your kids’ lives more fun right now.

For example, parents probably spend too much energy convincing their children to eat their vegetables and learn the piano, given that it won’t affect whether they will eat healthy as adults or be more intelligent. No one likes fighting. If you want your kid to learn the violin so they’ll have fun right now, it may very well be worth it, but don’t do it because you think it will increase their future income or intelligence. If neither you nor your child likes doing an activity, consider whether you can stop doing it.

Adoption studies provide good evidence that most activities don’t have a much of a long term effect on your children, so you need good evidence to start thinking that an activity will be good for your kids future. The odds are against it.

Have more kids

Focusing more on making your and your children’s lives more fun means that overall, having kids should be more attractive. If having another kid no longer means fighting about finishing their broccoli every night, maybe it’s not such a bad idea. On the margin, you should consider having more kids. If you were planning to have zero kids, consider having one. If you were planning to have 3 kids, consider 4, etc.

Other Topics

In much of the rest of the book Caplan gives common sense advice for making parenting easier for the parents. A couple of these, such as the Ferber method for dealing with infant sleep problems, are empirically based.

Here are some other topics Caplan discusses in his book:

  • Happiness research on parenting. Caplan argues that although being a parent seems to make people less happy, the effect is small (Ch 1).
  • Child safety statistics. Children are many times safer than in decades past (Ch 4).
  • Many of the benefits of having children come later in life (e.g. having people who will come and visit you, etc.), which makes it psychologically easy to ignore these benefits (Ch 5).
  • The externalities of children. He argues that on net, extra people have large positive externalities (Ch 6), so you shouldn’t feel guilty for having more children.

What parts should I read?

We wholeheartedly recommend reading the first 5 chapters (121 pages) of Selfish Reasons To Have More Kids as these have the most useful parts of the book; the rest of the book is less valuable. 

Criticisms of Selfish Reason To Have More Kids

There are a number of criticisms relevant to Caplan’s arugments. For example:

  • Nisbett claims that heredity is much less important for IQ than thought (see also counterclaims posted below).
  • Will Wilkinson claims (one, two) that the cost of parenting plays a small role in people's family size decisions, thus it's not a very strong reason to have more kids.
  • Jason Collins likes the book but would like it to discuss the research on non-shared environment (i.e. that not explained by genetic or parenting differences, such as peer effects) (link).