XX male syndrome
XX male syndrome, also known as de la Chapelle syndrome or 46,XX testicular disorder of sex development (or 46,XX DSD) is a rare condition in which an individual with a 46,XX karyotype develops a male phenotype. In 90 percent of these individuals, the syndrome is caused by the father's Y chromosome's SRY gene being atypically included in the crossing over of genetic information that takes place between the pseudoautosomal regions of the X and Y chromosomes during meiosis in the father.