Deletions in the azoospermia factor region AZFa on the human Y chromosome and, more specifically, in the region that encompasses the ubiquitin-specific peptidase 9, Y-linked gene USP9Y have been implicated in infertility associated with oligospermia and azoospermia. We have characterized in detail a deletion in AZFa that results in an absence of USP9Y in a normospermic man and his brother and father. The association of this large deletion with normal fertility shows that USP9Y, hitherto considered a candidate gene for infertility and azoospermia, does not have a key role in male reproduction. These results suggest that it may not be necessary to consider USP9Y when screening the Y chromosome of infertile or subfertile men for microdeletions