Incest can be defined as sexual activity with a person from within the immediate family. It is often considered synonymous with intrafamilial sexual abuse,1 although the broader term 'incest' can include consensual and non-consensual relationships between adults who are related to one another.2 The exact relationships which can be construed as incest will vary from culture to culture. Sexual relationships between first-degree relatives are a universal taboo in modern cultures, as are sexual relationships between second-degree relatives. The acceptability of sexual activity, and marriage, between first cousins varies substantially between cultures; in some, it is considered incest and forbidden, whereas in others, it is viewed favourably and encouraged.
This is a companion discussion topic for the original article at https://patient.info/doctor/paediatrics/incest