Throughout the world the intensity of religious commitments, i.e. religiosity, is positively linked to fertility, such that more religious people generally have more children. Whether beliefs and/or socio-economic factors drive this relationship is a point of discussion (McQuillan, K. 2004), but either way variation in fertility by religiosity must be achieved by affecting behavior. In this study we aim to test the hypothesis that age at marriage, which has been independently correlated with both religiosity and fertility, mediates this observed association. To test this hypothesis, we plan to use a generalized structural equation model using data from Matlab Bangladesh from married women interviewed in 2010 and again in 2018.