Stevens, Nettie Maria


Nettie Stevens has been recognised recently for her careful research postulating that the chromosomes are involved in the inheritance of a specific character, sex. The background of her achievement is discussed, including the behaviour of the chromosomes in cell division, the results of experimental breeding, and the possibility that the two are related. Through exploring her early life and education, her relationship to her colleagues who, while praising her work, did not give her the credit she deserved, and the professional difficulties that she as a woman encountered, Stevens’ importance in the history of genetics is considered.

Key Concepts:

  • Nettie M. Stevens is most noted for postulating that sex is determined by a specific chromosome.

  • Stevens shares credit for this discovery with Edmund B. Wilson.

  • Wilson is more often credited for this discovery both because he made more contributions to the history of biology and because Stevens was a woman.

  • The discovery of the sex chromosome helped establish the idea that chromosomes were responsible for the inheritance of a specific characteristic, sex.

Keywords: chromosomes; cytology; Walter S. Sutton; Edmund B. Wilson; cytogenetics; Thomas Hunt Morgan; Tenebrio molitor; spermatogenesis; oogenesis; heterochromosomes

Figure 1.

Nettie Maria Stevens in 1904. Courtesy of the Carnegie Institution of Science.

Figure 2.

Chemistry laboratory, Dalton Hall, Bryn Mawr College, 1899. Courtesy of Bryn Mawr College Archives.

Figure 3.

Nettie M. Stevens, Stazione Zoologica, Naples, Italy, 1909. Courtesy of Mrs. Helen M. Redfern and Clifford J. Choquette. From the scrapbook of Emma J. Stevens.



Morgan TH (1912) The scientific work of Miss N. M. Stevens. Science 36(928): 468–470.

Ogilvie MB (1991) The ‘New Look’ women and the expansion of American zoology: Nettie Maria Stevens (1861–1912) and Alice Middleton Boring (1883–1955). In: Benson KR, Maienschein J and Rainger R (eds) The Expansion of American Biology, pp. 52–79. New Brunswick, NJ: Rutgers University Press.

Ogilvie MB and Choquette CJ (1981) Nettie Maria Stevens (1861–1912): her life and contributions to cytogenetics. Proceedings of the American Philosophical Society 125(4): 292–311.

Robinson EE and Edward PC (eds) (1960) The Memoirs of Roy Lyman Wilbur – 1875–1959. Stanford: Stanford University Press.

Rosser SV (2004) The Glass Ceiling: Academic Women Scientists and the Struggle to Succeed. New York: Routledge.

Rossiter MW (1982) Women Scientists in America: Struggles and Strategies to 1940. Baltimore: Johns Hopkins University Press.

Stevens NM (1905) Studies in Spermatogenesis with Especial Reference to the Accessory Chromosomes. Washington DC: Carnegie Institution of Washington, DC. Carnegie Institution Publication No. 36, part 1.

Sutton WS (1903) The chromosomes in heredity. Biological Bulletin 4: 231–251.

Wilson EB (1905) Studies on chromosomes. I. The behavior of the idiochromosomes in Hemiptera. Journal of Experimental Zoology 2: 373–405.

Further Reading

Abir‐Am PG and Outram DA (eds) (1987) Uneasy Careers and Intimate Lives. Women in Science. New Brunswick, NJ: Rutgers. 1789–1979.

Allen GE (1966) Thomas Hunt Morgan and the problem of sex determination, 1903–1910. Proceedings of the American Philosophical Society 110: 48–57.

Brush SG (1978) Nettie M. Stevens and the discovery of sex determination by chromosomes. Isis 69: 163–172.

McClung CE (1902) The accessory chromosome – sex‐determination. Biological Bulletin 3: 45–48.

Ogilvie MB and Harvey J (eds) (2000) The Biographical Dictionary of Women in Science, Pioneering Lives from Ancient Times to the Mid‐20th Century, vol 2. New York: Routledge.

Wilson EB (1937) The Cell in Development and Heredity. New York: Macmillan.

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Ogilvie, Marilyn Bailey(Jul 2012) Stevens, Nettie Maria. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0023948]