There are a lot of graphs on the topic here[1]. Income isn't explicitly controlled for, but correlated characteristics like education level and IQ are. IQ appears to be strongly anti-fertile for liberal men and slightly pro-fertile for conservative men. 53% of the smartest group of liberal men age 35-44 had no children in the GSS data from 1995-2012[2a] compared to just 21% of conservatives[2b]. The differences with women are smaller but similar.
It should be noted that regardless of one's political beliefs, our modern culture can broadly be considered "liberal" and it is an extreme conservative indeed that doesn't guzzle down liberal books, movies, and television. Thus, while conservatism increases your fertility at the margin, white Americans of all political persuasions are having fewer kids than they used to[3].
It should be noted that regardless of one's political beliefs, our modern culture can broadly be considered "liberal" and it is an extreme conservative indeed that doesn't guzzle down liberal books, movies, and television. Thus, while conservatism increases your fertility at the margin, white Americans of all political persuasions are having fewer kids than they used to[3].
[1] http://jaymans.wordpress.com/2013/07/12/whos-having-the-babi...
[2a] http://jaymans.wordpress.com/2013/07/12/whos-having-the-babi...
[2b] http://jaymans.files.wordpress.com/2013/07/conserv-by-iq-kid...
[3] http://jaymans.files.wordpress.com/2012/08/lib-cons-cohorte....