Technological progress is reshaping the nature versus nurture debate of disease causation. Fifty years ago, psychiatrists used to argue over whether schizophrenia was caused by a single gene or some unknown environmental factor. We now know that there exist a range of component causes, or risk factors, for schizophrenia, both genetic and environmental. So, what do we argue about now? Often the relative importance of the 2 sets of factors. The favorite measure of geneticists has been heritability, often quoted as 60%–80% for schizophrenia, but this disregards the evidence that heritability estimates are inaccurate in the presence of gene-environment correlations or interactions.1