Birth order pairings and romantic success

The possibility that birth order influences romantic compatibility has long intrigued the lay public. In the absence of empirical research a marital advise literature has emerged, based on the observations of counselors and clinical psychologists, which purports to explain marital success in terms of birth order pairings. The present paper has two parts. In the first, using population register data from Sweden, we investigate the propositions about birth order and romantic relationships that are prevalent in the popular literature and show they have little validity. In the second, we undertake our own analysis which reveals two major birth order impacts: (a) a pronounced only-child effect, in that couples in which either spouse is an only have a divorce rate notably higher than couples in which neither is an only-child; and (b) for males, a protective effect from divorce from marriage with a first-born female, an outcome that does not hold for females in their own pairing choices.