We need to find out the extent to which individual differences, social class differences and race differences in rates of cognitive development, and differential patterns of relative strength and weakness are attributable to genetically conditioned biological growth factors. The answers to this question might imply differences in our approach to improving the education of all children, particularly those we call the disadvantaged, for many of whom school is now a frustrating and unrewarding experience. Dealing with children as individuals is not the greatest problem. It is in our concern about the fact that, when we do so, we have a differentiated educational program, and children of different socially identifiable groups may not be proportionately represented in different programs. Many environmentally caused differences can be minimized or eliminated, given the resources and the will of society. The differences that remain are a challenge for public education. It is the responsibility of educators to create a diversity of instructional arrangements best suited to the full range of educational differences. (Author/JM)