A welfare analysis of genetic testing in health insurance markets with adverse selection and prevention

Personalized medicine remains in its early stages, with expensive genetic tests offering limited actionable insights for prevention. As a result, few individuals undergo testing, and health insurance contracts pool all agents regardless of genetic background. However, as tests become cheaper and more informative, more people may choose to get tested, influencing both insurance pricing and contract types. We examine how the proportion of individuals taking genetic tests and the informativeness of these tests affect whether equilibrium contracts remain pooling or become separating. We find that increasing test uptake can reduce welfare, particularly when it leads to a shift from pooling to separating contracts. Similarly, lower prevention effort costs, reflecting more informative tests, can harm welfare if they induce separation. These findings suggest that policies promoting genetic testing or reducing prevention costs may not always be beneficial, especially when the market equilibrium remains in a pooling state.