a gene on the y chromosome that determines maleness is
Y chromosome The Y chromosome is one of two sex chromosomes (allosomes) in mammals, including humans, and many other animals. The other is the X chromosome. Y is the sex-determining chromosome in many species, since it is the presence or absence of Y that determines the male or female sex of offspring produced in sexual reproduction. In mammals, the Y chromosome contains the gene SRY, which triggers testis development. The DNA in the human Y chromosome is composed of about 59 million base pairs.[5] The Y chromosome is passed only from father to son. With a 30% difference between humans and chimpanzees, the Y chromosome is one of the fastest-evolving parts of the human genome.[6] To date, over 200 Y-linked genes have been identified.[7] All Y-linked genes are expressed and (apart from duplicated genes) hemizygous (present on only one chromosome) except in the cases of aneuploidy such as XYY syndrome or XXYY syndrome. (See Y linkage.)
Hermaphrodite Hermaphrodite is used in older literature to describe any person whose physical characteristics do not neatly fit male or female classifications, but the term has been replaced by intersex. Intersex describes a wide variety of combinations of what are considered male and female biology. Intersex biology may include, for example, ambiguous-looking external genitalia, karyotypes that include mixed XX and XY chromosome pairs (46XX/46XY, 46XX/47XXY or 45X/XY mosaic).