Passage: Since her death, McClintock has been the subject of a biography by the science historian Nathaniel C. Comfort's The Tangled Field: Barbara McClintock's Search for the Patterns of Genetic Control. Comfort's biography contests some claims about McClintock, described as the "McClintock Myth", which he claims was perpetuated by the earlier biography by Keller. Keller's thesis was that McClintock was long ignored or met with derision because she was a woman working in the sciences. For example, when McClintock presented her findings that the genetics of maize did not conform to Mendelian distributions, geneticist Sewall Wright expressed the belief that she did not understand the underlying mathematics of her work, a belief he had expressed towards other women at the time. In addition, geneticist Lotte Auerbach recounted that Joshua Lederberg returned from a visit to McClintock's lab with the remark: 'By God, that woman is either crazy or a genius.' " As Auerbach tells it, McClintock had thrown Lederberg and his colleagues out after half an hour 'because of their arrogance. She was intolerant of arrogance ... She felt she had crossed a desert alone and no one had followed her.'"Comfort, however, asserts that McClintock was well regarded by her professional peers, even in the early years of her career. Although Comfort argues that McClintock was not a victim of gender discrimination, she has been widely written about in the context of women's studies. Most recent biographical works on women in science feature accounts of her experience. She is held up as a role model for girls in such works of children's literature as Edith Hope Fine's Barbara McClintock, Nobel Prize Geneticist, Deborah Heiligman's Barbara McClintock: Alone in Her Field and Mary Kittredge's Barbara McClintock. A recent biography for young adults by Naomi Pasachoff, Barbara McClintock, Genius of Genetics, provides a new perspective, based on the current literature.On May 4, 2005, the United States Postal Service issued the "American Scientists"...

Question: How many Nobel prize winners were illustrated on American Scientists" stamps in 1989?
eight