Although the term genetic engineering has been in use for at least three decades, and recombinant DNA methods are now mainstays of modern research, most biotechnologists' work with living things has little in common with engineering. One reason is that the tools available for building with biological parts have yet to reach a level of standardization and utility equal to that in other engineering fields. Another has to do with methods and mind-sets in biology, although these, too, can be powerfully influenced by technology.
Electronic engineering, for example, was transformed beginning in 1957, when Jean Hoerni of Fairchild Semiconductor, a small company in what would later be known as Silicon Valley, invented planar technology. It was a system for layering and etching metals and chemicals within silicon wafers using templates called photomasks. This new approach allowed engineers to produce integrated circuits cleanly and consistently and to create a wide variety of circuit types just by changing the pattern on the photomask. Soon engineers could draw from libraries of simple circuits made by others and combine them in increasingly complex designs with a widening range of applications.