Stanley Norman Cohen is an American geneticist.
Cohen is a graduate of Rutgers University, and received his doctoral degree from the University of Pennsylvania School of Medicine in 1960. Following subsequent training at various institutions, including the National Institutes of Health, he joined the faculty of Stanford University in 1968.
It was there that he began to explore the field of bacterial plasmids. He wanted to understand how the genes of plasmids could make bacteria resistant to antibiotics. Cohen's investigations in 1972, combined with those of Paul Berg and Herbert Boyer, led to the development of methods to combine and transplant genes. This discovery signaled the birth of genetic engineering and earned Cohen the National Medal of Science in 1988. He also co-authored a proposal for uniform nomenclature for bacterial plasmids.
Today, Cohen is a professor of genetics and medicine at Stanford, where he works on a variety of scientific problems including cell growth and development.