Into the cells of people and several other organisms the sex chromosomes contain a set of chromosomes called the X and Y chromosomes. The X and Y chromosomes were first found in beetles by Nettie Stevens in 1906. She realized that cells of feminine beetles had identical searching pairs of each and every of these a few chromosomes, but that male beetles had one set when the chromosomes had been different in features from one another. She called those two chromosomes the X together with Y, and discovered that female beetles differed from men in containing two X chromosomes. The situation that is same also present in people where females are XX and men are XY.

The X and Y chromosomes in humans will also be completely different in features, with all the X chromosome being quite a bit bigger than the Y.

The X and Y chromosomes do not contain the same genes, unlike the other twenty-two pairs of human chromosomes in which members of a pair share all the same genes with the exception of only about nine shared genes. The Y chromosome offers the genes for determining a male pattern of development, as well as in the lack of a Y chromosome an embryo will observe a female pattern of development.

The intercourse of a person depends upon which sex that is paternal (X or Y) is inherited at fertilization .