XY

From X chromosome + Y chromosome.

XY

1. (biology) Having a male configuration of chromosomes as per the XY system.
   • 1973, E.W. Caspari, Advances in Genetics (in English), →ISBN, page 334:

     For example. copulation of females with sterile males carrying deficient Y chromosomes lay as many eggs as do females inseminated by normal XY males.

   • 1994, R. V. Short, E. Balaban (eds), The Differences between the Sexes, page 15, →ISBN.

     There is evidence to show that, occasionally, XY germ cells can undergo oogenesis when in an ovarian environment.

   • 2009, Gerald N. Callahan, Between XX and XY: Intersexuality and the Myth of Two Sexes (in English), →ISBN, page 30:

     The group at John Hopkins, as well as many others, dropped the "true sex" policy (such as XX or XY) and adopted the "optimal gender" policy for assigning sex to sexually ambiguous children.

2. (biology) Synonym of ZW (“having a female configuration of chromosomes as per the ZW system”)

• XX

• ZZ, ZW