His work revolutionized the world of genetics, his contribution was substantial, But Nettie Stevens would still have to overcome some obstacles to get the recognition they deserve. First, because the scientific community, still obsessed in environmental contributions, soon embraced his theory, and then, because Nettie Stevens ’research coincided in time and conclusions with that of Edmund B.. Wilson, one of the leading geneticists of that time would receive priority discoveries. Her status as a woman automatically relegated her to the background, although the article published by Wilson in the journal Science mentioned that "her findings were in line with Nettie Stevens' observations.", which shows that the work of geneticist known Stevens and somehow recognized its priority.
historically, the value of the work of many women scientists has not been recognized in all its value. This is the case of Nettie Maria Stevens, a biologist extraordinary really making a substantial contribution to the genetic theory. He published around forty scientific papers, being his greatest contribution to science demonstrating that sex is determined by chromosomes private.
E. Wilson, at that time the best cytologist, was investigating the same problem (1905). Often, the discovery has been awarded to him, although the issue of priority has recently been discussed. Resulta evident, But, from the study of the dates on which they published their work, both came to the same conclusions independently. 
Nettie Stevens analyzed cell differentiation in embryos and in the study of chromosomes. If science had previously held that chromosomes were organized into long loops, Now Stevens drew a different picture: chromosomes exist as paired structures in cells. If the somatic cells of the females contained 20 large chromosomes, the men had 19 big and small, 9 pairs of large chromosomes and consists of a large and a small. 
Studying the process of fertilization and egg tissues, Stevens was the first to recognize that females have two X sex chromosomes shaped and males have one X and one full size missing a portion, making him look like a Y. Wilson conducted tests only in the testicles, because the eggs were too fatty for staining procedures. After his discoveries, Wilson returned to his original article published and recognized by this finding Stevens.
It is a classic case of “Matilda effects”, a term called the abolitionist Matilda Gage. The effect is the phenomenon that the achievements of women tend to be co-opted, opacats directly or stolen by those of male counterparts. Stevens is far from the only woman who has this happen to her: Rosalind Franklin, whose work was crucial to the discovery of DNA, it was similar to the late twentieth century.