Family Norms and Declining First-Marriage Rates: The Role of Sibship Position in the Japanese Marriage Market

This study explores how changes in sibship composition associated with fertility decline may, in conjunction with entrenched family norms and expectations asso­ci­ated with spe­cific sibship posi­tions, impact mar­riage rates and fur­ther reduce fer-til ity. We evaluate this possibility by focusing on Japan, a society characterized by half a cen­tury of below-replace­ment fer­til­ity and widely shared fam­ily norms that asso­ci­ate eldest (male) chil­dren with spe­cific fam­ily obli­ga­tions. Harmonic mean mod­els allow us to quantify the contribution of changes in both marriage market composition with respect to sibship posi­tion and sibship-spe­cific pairing pro­pen­si­ties to the observed decline in mar­riage rates between 1980 and 2010. One impor­tant find­ing is that marriage propensities are lower for those pairings involving men and women whose sibship posi­tion sig­nals a higher poten­tial of care­giv­ing obli­ga­tions, espe­cially only-chil­dren. Another is that changes in mar­riage pro­pen­si­ties, rather than chang­ing sibship com-po sition, explain most of the observed decline in marriage rates. We also found that marriage propensity changes mitigate the impact of the changing sibship composition to some extent. However, the lim­ited con­tri­bu­tion of chang­ing sibship com­po­si­tion to the decline in first-mar­riage rates pro­vi­des lit­tle sup­port for a self-reinforcing fer­til-ity decline via the relationship between changing sibship composition and marriage behavior.