Does a legal reform with patriarchal interpretations of the religious law codes affect the wellbeing of the children? In this study, we show that reforming the legal system by adopting a religious law, with high enforcement in some Nigerian states, affects a woman's bargaining power and utility outside marriage, which could adversely affect a child's wellbeing. We find empirical support for this framework by using a difference-in-differences design that exploits variation in the women's religion, the state of residence, and the period of reform enforcement in Nigeria. The findings of this paper reveal that women exposed to the reforms are likely to report poor health investment and poor health outcomes in their children. The potential pathways through which the reform affects child wellbeing include early marriage entry and a decline in a woman's intra-household bargaining power.