There has been criticism that the ‘genetic revolution’ heralded by the completion of the Human Genome Project has failed to meet the more optimistic expectations of 15 years ago and that patient outcomes have not materially improved. This column analyses the extent to which basic genetic science has fuelled early-stage drug innovation. The results suggest that alleged ‘slower-than-expected’ progress has been partly caused by the amount of complexity in human biology, which was unexpected prior to the Project’s completion but has been progressively revealed since then.