The effect of same-sex marriage laws on different-sex marriage: Evidence from the Netherlands

Mircea Trandafir
Université de Sherbrooke, Canada

It has long been argued that the legalization of same-sex marriage would have a negative impact on marriage. In this paper, I examine what happened to different-sex marriage in the Netherlands after the enactment of two laws: in 1998, a law that provided all couples with an institution almost identical to marriage---registered partnership---, and in 2001, a law that legalized same-sex marriage for the first time in the world. I construct a unique data set covering the period 1995--2005 by matching individuals from ten waves of the Dutch Labor Force Survey with their marriage and residence history from official records. I first estimate the first-marriage decision using a discrete-time hazard model with unobserved heterogeneity. I find that the marriage rate rose after the registered partnership law but fell after the same-sex marriage law. The effects of the two laws are heterogeneous across more liberal and more conservative locations. Next, I construct a synthetic control for the Netherlands as a weighted average of OECD member countries over the period 1988--2005. A comparison of the marriage rates in the Netherlands and the synthetic control confirms the findings from the individual-level analysis and a placebo test supports the validity of the results. The results suggest that same-sex marriage leads to a fall in the different-sex marriage rate, but not in the different-sex union (marriage plus registered partnership) rate. In contrast, same-sex registered partnership does not affect different-sex marriage negatively and the availability of an alternative institution increases the different-sex union rate.

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