incestophilia

From incest +‎ -o- +‎ -philia.

incestophilia (uncountable)

1. (rare) The love of incest.
   • 1922, International Medical and Surgical Survey: Urology

     Children show erotic ties to parents and brothers and sisters, though not before 4–6 years of age. Infantile incestophilia is manifested by sensations and phantasies; incestuous acts, even sexual acts, may occur among brothers and sisters.

   • 2005, "Dave Goldman", Incest & genetics (was Re: Well-written good to evil conversions?) (on newsgroup rec.arts.sf.written)

     For example, there seems to actually be a disinclination to mate with a near relative (given alternatives) (and yes, various forms of incestophilia abound, but still). But it also seems not to be based on any perception of relatedness, at least not in humans, but rather on whether you were brought up together.