She Invented That A digital museum of women in science

Scientist Exhibit

Nettie Stevens

Biology & Life Sciences

1861 – 1912 United States

Demonstrated the chromosomal basis of sex determination

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Nettie Stevens

Overview

About Nettie Stevens

Nettie Stevens investigated chromosomes in insects and identified a clear relationship between particular chromosomes and biological sex. Her work showed that male mealworms produced sperm carrying either an X or a Y chromosome, while eggs carried an X chromosome. The evidence helped establish chromosomal sex determination.

Scientific Contribution

Key Discovery

Chromosomal sex determination

Evidence that sex is determined by specific chromosomes, including the XY system.

Life Timeline

Important Moments

1903

career

Begins research at the Carnegie Institution's Station for Experimental Evolution

Stevens received support for experimental research on heredity and chromosome behaviour during the period in which she made her best-known discovery.

1905

discovery

Shows that sex is associated with X and Y chromosomes

Studying mealworm chromosomes, Stevens demonstrated that males produced two kinds of sperm carrying different sex chromosomes, providing evidence for chromosomal sex determination.

1905

publication

Publishes Studies in Spermatogenesis

Stevens published the chromosome observations that established her central role in the discovery of chromosomal sex determination.

Places & Networks

Institutions