We consider a dynamic model of investment in human capital where onedecision maker (the head of the household) builds up human capital stocks of his/her children. In a stochastic framework, tradeoffs between investments in (physical) assets and investments in human capital achieved by differentchildren within the family are modelled as resulting from risk diversification and differing opportunity costs of investments. We show how to specify the structural model as a system of simultaneous discrete choice equations so that itis estimable using panel or cross section data on children* school attendance. We estimate structural parameters using data from the Cote d'Ivoire in 1985/1986 using standard and simulated maximum likelihood techniques. Results indicate that returns to learning by doing are much larger than returns to school at least at young ages, that the estimated inter temporal substitution elasticity is quite large and that the elasticity of substitution between financial and human capitalassets is negative