Barbara McClintock was born on June 16, 1902, in Connecticut. The daughter of a physician, she grew up in the Flatbush section of Brooklyn, New York--a rural area during that time. During high school, McClintock's interests turned from sandlot baseball to science. Despite her parents' misgivings, she persuaded them to let her study at Cornell University, an agricultural college in Ithaca, New York. McClintock was fascinated with a genetics course she took in her junior year. However, in the plant breeding department where most of the genetics courses were taught, women were not permitted as graduate students. So McClintock signed up in the botany department and became assistant to a cytology professor who encouraged her interest in plant genetics.

After McClintock completed her graduate work at Cornell, she stayed on as an instructor and researcher, associating herself with Rollins Emerson's famous maize (corn) genetics group. During this time, she discovered...