Despite decades of precollege science education programs, African Americans, Latinos, and Native Americans remain critically underrepresented in science and health professions. This report describes college and career outcomes among graduates of the Stanford Medical Youth Science Program (SMYSP), a 5-week summer residential program for low-income high school students among whom 97% have been followed for up to 21 years. Approximately 24 students are selected annually, with participation limited to low-income students who have faced substantial personal hardships. Undergraduate and medical students provide key program leadership and training. The curriculum is based on science inquiry education and includes hospital internships, anatomy practicums, research projects, faculty lectures, college admissions/standardized test preparation, and long-term college and career guidance. A total of 476 high school students participated between 1988 and 2008, with 61% from underrepresented ethnic minority groups. Overall, 78% of African American, 81% of Latino, and 82% of Native American participants have earned a 4-year college degree (among those admitted to college, and excluding those currently attending college). In contrast, among 25-34-year old California adults, 16% of African Americans, 8% of Latinos, and 10% of Native Americans earn a 4-year college degree. Among SMYSP's 4-year college graduates, 47% are attending or have completed medical or graduate school, and 43% are working as or training to become health professionals. SMYSP offers a model that expands inquiry-based science education beyond the classroom, and recognizes the role of universities as "high school interventionists" to help diversify health professions.