The age-parity-nuptiality model so far considered by demographers does not allow single women to have children, and all births are attributed to married women. The present paper is an attempt to extend the age-parity-nuptiality model by removing this restriction on single women. Mathematical expressions for the computation of intrinsic rates from the integral equation and projection approaches are derived. The model is applied to the U.S. female population for the year 1970.