14.7: Incest

Incest is defined as sexual relations between people classed as family members or close relatives. Typically, this includes sexual activity between people who are blood related, or by marriage in the case of step-families. Most cultures have some taboo against incestuous relationships, although they vary between present day and historically. Of concern primarily would be the coercive potential of a family member asserting dominance over another family member in order to engage in a sexual encounter. This would be sexual assault and in the case of a minor child, child molestation which is a crime of any sexual act with a minor. Laws against incest likely arose after people observed the consequences of the ways in which certain health problems tended to run in families. Procreating with people who are in the same gene pool reduces the amount of genetic variation.

Incest between siblings is the most common form, with father-daughter being second most (Finkelhor, 1990). Children learn by experimenting and exploring in other realms of their lives, so sexual exploration, alone or with peers, is part of that. A parent’s role is to scaffold their child’s learning by providing healthy sex education that includes specific social and personal boundaries. This type of sex education can empower children to have agency over their bodies. Incest between siblings is the most common form; it may result out of natural curiosity and be non-coercive, and is seen as more innocuous than parent child (Finkelhor, 1990).

It may also be a form of abuse. Sibling sexual abuse (SSA) has been defined as sexual behavior between siblings that is not age appropriate, not motivated by natural mutual curiosity and usually happens more than once (Bertele & Talmon, 2021; Tener et al., 2021; Watts, 2020). It does not necessarily include physical force, but often involves coercion (Bertele & Talmon, 2021). In the context of SSA, sibling can refer to children that are raised together in a household. They could be biological siblings, step or half siblings, cousins, foster siblings or other children who live together (Watts, 2020).

According to Bertele and Talmon (2021) there is not one clear definition of SSA. It is sometimes confused with mutual consensual sibling sexual behavior that is part of healthy sexual development, which also has an unclear definition. Due to this confusion, sometimes what is abuse might get minimized by families, social workers or others who see it as natural sibling play (Bertele & Talmon, 2021; McCoy et al., 2021; Tidefors et al., 2010).

SSA may include “intercourse, attempted intercourse, oral–genital contact, fondling of genitals directly or through clothing, exhibitionism, exposing children to adult sexual activity or pornography, and the use of the child for prostitution or pornography” (Caffaro, 2017, p. 544).

Although it is thought to be the most common type of child sexual abuse, there is much silence around sibling sexual abuse (SSA), even more so than other interfamilial sexual abuse (Caffaro, 2017; Tener et al., 2021; Tidefors et al., 2010; Watts, 2020; Yates, 2020). There is evidence internationally that sibling abuse often goes unrecognized or is minimized by professionals from education, health and social care (Yates, 2020).

Any form of incest violates cultural taboos, and most societies sanction the behavior in differing ways. If the incest is between an adult and a minor, it is always considered child sexual abuse.