Mathematical model projections, based on our understanding of the predominant behaviour pattern and fitted to observed trends in HIV prevalence, also indicate that further increases in adult and early childhood mortality are to be expected. Results from these simulations and empirical findings from Uganda suggest that these increases will result in adverse indirect effects, including high proportions of children experiencing orphanhood and distortions in the age- and sex-distribution of the population [9,10]. These effects may be compounded by fertility change. Birth rates are declining in rural areas of Zimbabwe at present and the HIV epidemic may re-enforce this decline through changes in behaviour or underlying fecundity [11]. Women with HIV infection are reported as having lower fertility than other women in Ugandan studies [12] and results from our research in Manicaland indicate that behaviour changes which would tend to re-enforce the existing decline in birth rates may be beginning to occur [7].