XX
XX or xx may refer to: 20 (number), Roman numeral XX == Film and TV == XX (film), a 2017 anthology horror film "XX", an episode of CSI: Crime Scene Investigation (season 4) XX, the production code for the 1969 Doctor Who serial The Seeds of Death XX (web series), a 2020 South Korean web series XX (organization), a fictional organisation in the comic and game XIII == Genetics == XX sex chromosomes, in the XY sex-determination system XX male syndrome, also known as de la Chapelle syndrome, a rare congenital intersex condition resulting in a phenotypical male with two X chromosomes XX gonadal dysgenesis, a type of female hypogonadism resulting in non-functioning ovaries XX sex chromosomes, in the XO sex-determination system a female, an organism producing ova gametes that fuse with the male gamete during sexual reproduction, typically having two X chromosomes in the XY and X0 sex determination systems == Music == The xx, an English indie rock band X_______X (band), an American no wave band === Albums === Toto XX, a 1998 album by Toto XX (Mushroomhead album), 2001 xx (The xx album), 2009 XX (Great Big Sea album), 2012 XX – Two Decades of Love Metal, a 2012 compilation album by HIM XX (O.A.R. album), 2016 XX (Mino album), 2018 XX, a 2018 album by Note-oriety + + (EP), a 2018 EP, repackaged as [X X] in 2019, by Loona XX, a 2026 album by Fally Ipupa === Songs === "xx", a song by Hayley Kiyoko from Expectations "XX", a song by Feid from Ferxxo (Vol 1: M.O.R) == Organisations == XX Bomber Command, an inactive United States Air Force unit XX Corps (disambiguation) Legio XX Valeria Victrix or Legion XX, a legion of the Roman Empire == Other uses == XX (novel), a 2020 novel by Rian Hughes XX System or Double-Cross System, a British deception operation in the Second World War Les XX, a group of twenty Belgian painters Dos Equis or XX, a brand of Mexican beer xx, to express exponentiation in the initial version of the FORTRAN programming language .xx ("dot XX") is sometimes used in documentation as a placeholder for an arbitrary Country code top-level domain in the Internet domain naming system, as it does not correspond to any real ccTLD or ISO 3166-1 alpha-2 country code.