We have developed a theoretical link between the existence of a son preference and the quantity and quality of children. In our model, decisions about the quantity and quality of children are interdependent and are influenced by a son preference. A son preference substantially widens the gap between the quality of female and male children, and increases the possibility of having more children to realize this preference. An increase in the level of son preference lowers the average level of education, especially for female children. For households with a son preference, having a female birth at each birth order significantly increased the probability of having more children, with a magnitude which is much larger than that suggested in Dahl and Moretti (2008). More interestingly, once such households have a son, there is a significant reduction in that household’s likelihood of having more children. Furthermore, our findings establish the causal effect of a son preference on the quantity and quality of children within a family as a son preference is found to greatly reduce households’ sensitivity to the change in the shadow price of quantity as well as quality.