A 1905 research paper with a long-winded title - "Studies in Spermatogenesis with Especial Reference to the 'Accessory Chromosome'" - written by Bryn Mawr biologist Nettie Stevens, was one of the 20th century's major scientific breakthroughs, showing that the chromosomes known as "X" and "Y" were responsible for determining the sex of individuals. This ended a longstanding scientific debate as to whether sex was determined by heredity or other factors.

Now, once and for all, a relatively obscure research biologist had shown that chromosomes influenced human traits, opening the doors for research in science and medicine that continues to this day.

Nettie Stevens, educated at Stanford University and Bryn Mawr College (Ph.D., 1903), taught throughout her relatively short life, inspiring many students to careers in science. She published more than 38 papers from 1901 to her death, in cytology and experimental physiology.

Additional Resources:
Nies, Kevin Allison. From Priestess to Physician. Science Kit, Inc., 1996.

Veglahn, N. American Profiles: Women Scientists. New York: Facts fo File, Inc., 1991.

Papers ca. 1905-1978. 1 box. Bryn Mawr College, Archives and Manuscripts. Bryn Mawr, Pennsylvania.