When the pot-smoking, financially irresponsible protagonist in the 2007 comedy Knocked Upbecomes an expectant father, he attempts to reconcile his life with impending fatherhood. He bids adieu to his slacker roommates and their dreams of launching a celebrity porn website, and we next see him painting a nursery in a newly procured apartment. The biggest change of all: Taking a job in an office.
This illustrates something people have long assumed: The responsibilities associated with fatherhood motivate men to work a bit harder and move into more lucrative careers. Harvard sociologist Alexandra Killewald had certainly read research that corroborated this theory, but wondered if "the fatherhood premium," which asserts that entry into fatherhood will produce wage gains if it prompts altered behavior, held true for all dads.
In the forthcoming paper in next month's American Sociological Review, "A Reconsideration of the Fatherhood Premium: Marriage, Coresidence, Biology, and the Wages of Fathers," Killewald shows that the wage gain does in fact exist, but that boost is not available to everyone.
Killewald found that married, biological fathers who live with their families are associated with a wage bonus of about four percent after they have kids. Unmarried fathers, fathers who do not live with their children, and stepfathers do not receive this premium.