The major policy response to high rates of population growth in developing countries has been wide-scale national family planning programs, whose primary function is distributing contraceptives. The implicit "model" underlying this family planning response neglects several important factors. This Note sketches an alternative model which has been used to analyze breastfeeding, contraceptive use, birthspacing, and infant mortality using data from the Malaysian Family Life Survey. This model considers both the biomedical influences of breastfeeding and contraceptive use on birthspacing and the behavioral mechanisms that trigger these biomedical relationships. Main findings and policy implications are discussed, including effects of community supplies of contraceptive and baby foods, and effects of women's job characteristics.