Does the Combination of Spouses’ Birth Orders Influence Their Divorce Risk? Evidence from a register-based study of Norwegian first marriages

Unions of individuals with different birth orders have been suggested to be more stable than those of individuals with the same birth order. One reason why spouses’ birth orders may influence marital stability is that sibship position affects personality, and certain personality combinations are more compatible than others. First-borns may have more dominant personalities and unions of two first-born individuals, where both are dominant, may be more likely to break up. Likewise, marriages of two youngest siblings are said to be relatively unstable relationships (Leman 1998, Toman 1976).