Stanley Norman Cohen (born February 17, 1935) is an American geneticist[2] and the Kwoh-Ting Li Professor in the Stanford University School of Medicine.

[3] Stanley Cohen and Herbert Boyer were the first scientists to transplant genes from one living organism to another, a fundamental discovery for genetical engineering.

[4][5] Thousands of products have been developed on the basis of their work, including human growth hormone and hepatitis B vaccine.

[6] According to immunologist Hugh McDevitt, "Cohen's DNA cloning technology has helped biologists in virtually every field".

"[7] Boyer cofounded Genentech in 1976 based on their work together, but Cohen was a consultant for Cetus Corporation and declined to join.

[10] During a residency at the National Institute for Arthritis and Metabolic Diseases, he decided to combine basic research with a clinical practice.

Plasmids were sent back and forth between Stanley Cohen, Annie C. Y. Chang, and others at Stanford, and Herbert Boyer and Robert B. Helling at the University of California, San Francisco.

The Stanford researchers isolated the plasmids, and sent them to the San Francisco team, who cut them using the restriction enzyme EcoRI.

[12] This collaboration, in particular the 1973 publication of "Construction of biologically functional bacterial plasmids in vitro" by Cohen, Chang, Boyer and Helling, is considered a landmark in the development of methods to combine and transplant genes.

[10][15] These discoveries signaled the birth of genetic engineering, and earned Cohen a number of significant awards, beginning with the Albert Lasker Award for Basic Medical Research in 1980 for "his imaginative and persevering studies of bacterial plasmids, for discovering new opportunities for manipulating and investigating the genetics of cells, and for establishing the biological promise of recombinant DNA methodology.

"[16] In 1976, Cohen co-authored a proposal for uniform nomenclature for bacterial plasmids (with Royston C. Clowes, Roy Curtiss III, Naomi Datta, Stanley Falkow and Richard Novick).

[10] He was a signatory of the "Berg letter" in 1974, which called for a voluntary moratorium on some types of research pending an evaluation of risk.

"[23] Today, Cohen is a professor of genetics and medicine at Stanford, where he works on a variety of scientific problems involving cell growth and development, including mechanisms of plasmid inheritance and evolution.