Patenting genes encoding therapeutic proteins was relatively uncontroversial in the early days of biotechnology. Controversy arose in the era of high-throughput DNA sequencing, when gene patents started to look less like patents on drugs and more like patents on scientific information. Evolving scientific and business strategies for exploiting genomic information raised concerns that patents might slow subsequent research. The trend towards stricter enforcement of the utility and disclosure requirements by the patent offices should help clarify the current confusion.