Y chromosome and male infertility

Recent genome analysis of the Y chromosome has increased the number of genes found on this chromosome markedly. Many of these genes in the part of the Y chromosome that does not undergo recombination with the X chromosome are members of gene families. Evolutionary considerations imply that genes on the Y chromosome will degenerate unless they have male advantageous or female deleterious functions. Spermatogenesis is an example of a male advantageous function and genes in three regions of the human Y chromosome have been promoted as candidate male fertility factors.