||Diagnostic research is important in helping to create an enabling environment for promising biotechnology products in smallholder agriculture, before rather than after release. The biotechnology products that now hold promise for poor people in Sub-Saharan Africa are those that tackle economically important, biotic or abiotic problems not easily addressed through conventional plant breeding or pest control, in crops that serve for food as well as cash, while posing little risk of endangering trade. Two biotechnology products we have selected for social science research in East Africa, Bt maize in Kenya and pest and disease resistance in the East African highland banana, meet these criteria. Preliminary research suggests that the expression of the trait is much more visible to farmers in maize than in bananas; for either crop, for different reasons, bottlenecks will be encountered in planting materials systems; and despite differing crop reproduction systems, transgenic varieties of either share the same environmental hazard of heightened genetic uniformity in the inserted trait relative to conventionally bred varieties. Aside from the performance of the technology, many factors that have incidence at national, regional, and farm levels will affect the likelihood that farmers will adopt transgenic varieties. Social science research can help pinpoint necessary complementary investments.