Lately I’ve often heard that family is the key divide between Democrats and Republicans.  Democrats are supposed to be single and childless, Republicans married with kids.  So I decided to check this out for myself in the General Social Survey

To be precise: What is the effect of being married (married=1, other=0) and number of kids on party identification, controlling for: log income, education, race, gender, age, year/1000, church attendance, and Biblical literalism?  (See my class notes (here, here, and here) for details on the variable definitions and coding). 

Over the entire sample (1972-2010), family variables have quite a small effect.  Being married made you 2.3 percentage-points less likely to be a Democrat, and 1.8 percentage-points more likely to be a Republican.  The effect of children was statistically insignificant – .3 percentage-points less Democratic per child, .1 percentage-points more Republican per child. 

Since most of the people pushing this thesis emphasize recent politics, I decided to limit the sample to 2000-2010.  Here’s what I found.

Conditional probability of being a Democrat:


More than in the past, for sure.  But still marginal, right?  The Republican results are similar:

The simplest explanation for my small estimates is that I’m controlling for church attendance and Biblical literalism.  If you drop these controls, marriage and children matter quite a bit more.  All things considered, though, the religious controls seem appropriate.  Religious belief, religious observance, marriage, child-bearing – these are all reflections of underlying traditionalism – and that’s probably what’s driving the results.

P.S. Controlling for ideology, the family variables make no difference at all.  Given the stability of ideology over people’s lives, the simplest explanation is that political ideology sways marriage and child-bearing as well as voting.