Sacerdote and Feyrer have an intriguing new paper on fertility. Background: Some rich countries – including Japan, Germany, Italy, Spain, and Greece – have extremely low fertility, while others – including the U.S., Sweden, and France – are only moderately below replacement. Sacerdote and Feyrer have a complicated explanation, but their most original claim is that national fertility variations are strongly affected by how much men help around the house:

[H]igh-income countries such as Italy, Spain, Germany, and Japan, where men do the smallest fraction of the household chores and child care… are also the high-income countries with the lowest fertility rates.

The paper is essentially a tale of gender conflict. When women bear almost all of the burden of housework, the marginal cost of children for women is very high, so their quantity demanded goes down. I don’t think that Sacerdote and Feyrer say so explicitly, but their analysis also implies that as the amount of housework that men do goes down, their quantity of children demanded goes up.

One problem with this model: It’s not entirely clear why family size would shrink when women want fewer kids AND men want more. With bargaining and side payments, it’s conceivable that the number of kids would actually rise.

But my main worry about this paper is the premise that men and women disagree about optimal family size. At least in the U.S., women and men see almost exactly eye-to-eye: Men say the optimal is 2.57, women say 2.56. If Sacerdote and Feyrer are correct, the U.S. pattern should be rare. In countries like Japan and Italy, where men do less housework than American men, men should want substantially more kids than women do. In countries like Sweden, when men do more housework than American men, men should want substantially fewer kids than women do. In other words, if this paper is correct, the (male/female ideal family size ratio) as a function of men’s share of the housework will exceed 1 at low levels of housework, equal 1 at the American level of housework, and then fall below 1 when men’s share of housework increases above the American level.

My guess, contrary to Sacerdote and Feyrer’s story, is that male-female agreement on ideal family size is the rule around the world. Men and women may disagree about how clean the house should be, but they agree about how many people it ought to contain. Does anyone know if I’m wrong?

P.S. I’ll be arriving at the Foundation for Economic Education’s Young Scholars Colloquium later today. If you see me there, please say hi. 🙂

P.P.S. I’ll be in NYC on Sunday night. If any readers want to meet up for dinner and/or gaming, email me.