Editing XY sex-determination system (section)

===Other animals===
Some species of [[turtle]]s have convergently evolved XY sex determination systems, specifically those in [[Chelidae]] and [[Staurotypinae]].<ref>{{cite journal | vauthors = Badenhorst D, Stanyon R, Engstrom T, Valenzuela N | title = A ZZ/ZW microchromosome system in the spiny softshell turtle, Apalone spinifera, reveals an intriguing sex chromosome conservation in Trionychidae | journal = Chromosome Research | volume = 21 | issue = 2 | pages = 137–147 | date = April 2013 | pmid = 23512312 | doi = 10.1007/s10577-013-9343-2 | s2cid = 14434440 }}</ref>

Other species (including most ''[[Drosophila]]'' species) use the presence of two X chromosomes to determine femaleness: one X chromosome gives putative maleness, but the presence of Y chromosome genes is required for normal male development. In the fruit fly individuals with XY are male and individuals with XX are female; however, individuals with XXY or XXX can also be female, and individuals with X can be males.<ref>{{Cite book|url=https://books.google.com/books?id=AKGsDwAAQBAJ|title=The Biology of Reproduction|vauthors=Fusco G, Minelli A|date=2019-10-10|publisher=Cambridge University Press|isbn=978-1-108-49985-9|pages=306–308|author-link2=Alessandro Minelli (biologist)}}</ref>