With nearly half of U.S. births occurring out of wedlock, understanding how parents navigate their relationship options is important. This paper examines the consequences of a large exogenous change to parental relationship contract options on parental behavior and child well-being. Identification comes from the staggered timing of state reforms that substantially lowered the cost of legal paternity establishment. I show that the resulting increases in paternity establishment are partially driven by reductions in parental marriage. Although unmarried fathers become more involved with their children along some dimensions, the net effects on father involvement and child well-being are negative or zero.