In this project we plan to explore the determinants of fertility and in particular of the relation between education, wages and fertility. In order to do this we build a model of household formation, where males and females choose whether to marry and how many children to have as well as the time allocation between market and non market activities, and the education decision. The outcome of the project is two fold (1) Understand the determinants of fertility using the variation in male and female education and wages over time as well. (2) Ask whether changes in wages and relative prices both of acquiring education and of home production substitutes are sufficient to account for the decline in the TCFR fertility or some other considerations are needed. What we have in mind here is an externality in the number of children that amplifies the effects of individual decisions and that induces a reduction in fertility over time for groups that have the same education only as a result of lower fertility of other people. This is our interpretation of what other social scientists have in mind about social norms or culture (Kohler (2001)).