Abstract
It was proposed that couples whose birth order duplicates interpersonal patterns with siblings (e.g. a couple consisting of firstborn and lastborn) should show higher relationship and sexual satisfaction. To test this hypothesis, we collected data from a sample of heterosexual pairs (N=555), where both partners had only one sibling.
We tested for assortative pairing, dyadic adjustment, and sexual compatibility. Our results suggest that the birth order of partners has no significant effect on relationship functioning.
These findings might be a due to focus on two-children families, which represent, however, the most common pattern in postindustrial countries. The birth order effects on relationship functioning might be limited to populations with a scarcity of resources and/or higher fertility rates.