Selfish Reasons to Have More Kids - Bryan Caplan

kids make you happy

kids are easier to raise than you think

Caplan's main point here is that the primary determinant on a kid's personality and intellect is genetic, so marry someone who remsembles the kids you want to have. [86]

When it comes to nurture, direct parental influence ("do this, don't do that") matters much less than the larger environment (neighborhood, school, extended family), so be around people who resemble the type of kid you want to have. [82] Garret Jones' Hive Mind and Steven Pinker's The Blank Slate have more to say about this.

A few other points:

why we don't have more kids