Woman of the Month: Nettie Stevens — Why XY?
Nettie Stevens was a brilliant cytogeneticist and biologist. Despite her contributions being largely attributed to others in her field, her discovery regarding the link between gender and chromosomes is the foundation of modern-day genetics.
Nettie was born on July 7, 1861, in Cavendish, Vermont but grew up in Westford, Massachusetts. She attended the town’s public schools, graduating from Westford Academy in 1880.
Surprisingly, for someone who ultimately had such an impact on our understanding of reproduction, there is a sixteen-year gap in Nettie’s documented history. All that is known is, during that time, she taught at a high school in Lebanon, New Hampshire.
In 1896, at age thirty-five, Nettie enrolled at Stanford University to study physiology. In her free time, she pursued her passion for, “ [learning] at the Hopkins Seaside Laboratory [in] Pacific Grove, California” (Nettie Stevens). At Hopkins, Nettie researched the life-cycle of a protozoan parasite of sea cucumbers, Bavaria and in 1901, the Proceedings of the California Academy of Sciences published her findings.
Upon completion of her master’s degree at Stanford, she relocated to Pennsylvania to attend Bryn Mawr College for a graduate degree in biology. An exemplary student, she was soon awarded a fellowship that allowed her to study at the Zoological Station in Naples, Italy, and to work with Theodor Boveri, a renowned biologist, at the University of Wurzburg’s Zoological Institute in Germany.
In 1903, Nettie obtained a Ph.D. from Bryn Mawr but remained there as a postdoctoral researcher.
At the time, many of her peers considered gender a direct result of environment and nutrition during development. Nettie believed differently, that gender was determined at conception. To study this theory, the Carnegie Institution provided Nettie with a grant. Investigating the reproduction of beetles, she noted that the sperm produced contained X or Y chromosomes and that unfertilized eggs contained two X chromosomes. From this, Nettie hypothesized that Y chromosome sperm would produce male embryos and X chromosome sperm would create female offspring. Despite Nettie’s hypothesis accurately predicting the chromosomes of the offspring, her “research was not accepted when she published her results in 1905” (Nettie Maria Stevens [Science and Its Times]). A co-worker, Edmund Wilson deemed Nettie’s results implausible but would later go on to conduct similar experiments, leading to him receiving credit for this discovery and “later texts have focused credit more onto E.B. Wilson and his colleagues, undeservedly reducing her stature, or worse yet failing to mention [Nettie] at all” (Nettie Maria Stevens [Science and Its Times]).
Despite being overshadowed, there are still those who recognize the weight of Nettie’s influence. “By the late twentieth century, [Nettie] was identified as the scientist who recognized the fundamental genetic concept that chromosomes determine gender at conception” (Nettie Maria Stevens [Science and Its Times]). When Thomas Hunt Morgan received the Novel Prize in 1933 for his work in genetics, he recognized Nettie in his speech stating that she “had a share in a discovery of importance and her name will be remembered for this, when the minutiae of detailed investigations that she carried out have become incorporated in the general body of the subject” (Nettie Stevens).
Similar to Rosalind Franklin, whose discoveries regarding the structure of DNA fifty years later would be overshadowed by her male peers (See Woman of the Month: Rosalind Franklin, Mother of the Helix to learn about this inspiring “Mother of the Helix”), Nettie Stevens faced adversity at every turn. Despite data backing up Nettie’s findings regarding the connection between chromosomes and gender, her theory was deemed impossible and was only accepted when a male colleague carried out the same experiment. It is abhorrent that it took a man for these findings to be accepted, especially considering that very man openly bashed Nettie’s findings and declared them implausible.
As I have written each of the articles in this column, this idea of being overshadowed by men is a theme throughout, and the idea that women cannot receive recognition for their discoveries, innovations, and brilliance needs to end. We are in the 21st century. We are done waiting until tomorrow to receive the accolades we earn. As I graduate from high school, the same one Nettie Stevens graduated from, I am excited to be a part of what enables us, the women of today, to be acknowledged and held up in society.
