Janet E. Mertz (born 1949) is an American biochemist, molecular biologist, and cancer researcher. She is currently the Elizabeth McCoy Professor of Oncology in the McArdle Laboratory for Cancer Research at the University of Wisconsin – Madison. Mertz is best known for disputing Lawrence Summers’ 2005 suggestion that women lack the intrinsic aptitude to excel in mathematics at the highest level and for discovering an easy method for joining together DNAs from different species . This latter finding initiated the era of genetic engineering whose ramifications form the basis of modern genetics and the biotechnology industry.