Nettie Stevens Poster

Teacher Description

Nettie Stevens (1861–1912) was an American geneticist whose pioneering research transformed our understanding of heredity. In 1905, she provided strong scientific evidence that sex is determined by the X and Y chromosomes in many animals, including humans. Her careful observations under the microscope helped lay the foundations of modern genetics. Although her work was not fully recognised during her lifetime, Nettie Stevens is now celebrated as one of the most important scientists in the history of biology. Her dedication, curiosity and perseverance continue to inspire future generations of scientists.