Wikipedia
"S-E-X-X-Y" is a single released in 1996 by musical group They Might Be Giants, alongside their sixth album, Factory Showroom. It was the lead single from Factory Showroom.
Lyrically, the title track revolves around an attractive woman. They Might Be Giants have directly claimed that this song is simply an "ode to getting it on." The song states that "X, because it's extra, baby; Y, because it's extra, baby," to imply that the X and Y are extraneous, leaving only " S-E-X". However, it's possible to interpret the song as a depiction of a person with Klinefelter's syndrome — a person with two X chromosomes and a Y chromosome, or possibly a transgender person, as evidenced by the final lyrics of the song: "You gotta understand; she wants to be your man; she's got another plan". These theories have been denied by author John Flansburgh.