Under the tender years doctrine in effect until the 1970's, custody was virtually always awarded to the mother upon divorce. Gender-neutral custody laws introduced beginning in the 1970's provided married fathers, in principle, equal rights to custody. Subsequent marriage-neutral laws extended the rights to unmarried fathers. We develop a theoretical model of the effect of custody regime on marriage and test the model's predictions using a unique data set that merges custody law data with data from the Current Population Survey and Vital Statistics. We find that, under marriage non-neutrality, the introduction of gender-neutral laws reduced the hazard into marriage by at least 7.9 percent. There is no evidence that moving from marriage non-neutrality to marriage neutrality affected marriage under the gender-neutral custody regime.