The " pipeline " model of STEM education conceives of underrepresentation by race, gender and class in terms of leaks that fail to deliver students to their destination in the science and technology workforce. But that model fails to consider the role of STEM in producing underrepresentation. This can only be solved by moving from the extractive approach of the pipeline model to a generative model in which the value produced by STEM students cycles back to their own communities. We report on our experience creating and evaluating Culturally Situated Design Tools. Using a framework of " generative justice " , we contrast the cyclic social damage, which reproduces underrepresentation with the potential for STEM education as a niche in the technosocial ecosystem that can address underrepresentation and causal factors.