Professional Reference articles are designed for health professionals to use. They are written by UK doctors and based on research evidence, UK and European Guidelines. You may find one of our health articles more useful.
Treatment of almost all medical conditions has been affected by the COVID-19 pandemic. NICE has issued rapid update guidelines in relation to many of these. This guidance is changing frequently. Please visit https://www.nice.org.uk/covid-19 to see if there is temporary guidance issued by NICE in relation to the management of this condition, which may vary from the information given below.
What is incest?
Incest can be defined as sexual activity with a person from within the immediate family. It is also called intrafamilial sexual abuse. However, the exact relationships which can be construed as incest will vary from culture to culture. Many countries have laws that forbid incest but there is considerable variation in the exact nature of these.
In England and Wales the Sexual Offences Act 2003 created an offence of familial sexual abuse (this is covered in Scotland in the 2009 Sexual Offences Act, and in Northern Ireland in the Sexual Offences Order 2008). The aim of this law was to protect children up to the age of 18 from any form of activity that a person would consider sexual or indecent. The offender may be an adult or another child. It recognises the modern family unit and it defines familial sexual abuse as being between a person and their parent (including adoptive or foster), grandparent, child, grandchild, sibling or half-sibling, uncle, aunt, nephew or niece.
The Sexual Offences Act 2003 also prohibits adult sexual relationships but within a slightly narrower definition that includes just close blood relationships only - parent, grandparent, child, grandchild, older brother, sister, half-brother, half-sister, uncle, aunt, nephew or niece.
The most common manifestations are sibling incest and father-daughter incest.
How common is incest? (Epidemiology)
Sibling sexual abuse is usually recognised as being the most common form of sexual abuse within families. It has been documented as being five times more common than father/stepfather abuse. Father-daughter incest was reported by 2.5% of female participants in an anonymous computer-assisted self interview. One study from Scandinavia looked at all child sexual abuse in one area:
- Girls were victims in 85% of the cases, boys in 12% and boys as well as girls in 3%.
- Sexual penetration had occurred in 53.7% of cases and there was genital or other physical manipulation in 29.6%.
- In 16.7% of cases there was no physical contact but there was some kind of non-contact molestation or exhibitionism.
- Most perpetrators (72%) were well known to the child.
- The most severe violations (regarded as the ones where there was sexual penetration) were significantly more often committed by biological relatives, household members, or family friends than by strangers.
Concerns have been raised that fewer reports of child abuse were made during the COVID pandemic. Future research will show the impact of the pandemic on family dynamics and intrafamilial abuse.
Presenting features of incest
See the separate Safeguarding Children - How to Recognise Abuse or a Child at Risk article.
The offender is reported as male in most cases but female involvement may be under-reported. Although sibling incest is thought to be the most frequently occurring form of incest, the abuse of daughters by fathers or stepfathers is more commonly reported. Abuse by stepfathers is up to five times higher than that by biological fathers. Physical symptoms may include:
Incest is usually repeated and will often continue for many years. As the daughter reaches an age when she may be able to resist or flee, the activity may be repeated with a younger sister. Though the profiles of incestuous families may vary, the father-perpetrator is typically an immature individual with low self-esteem, while the wife-mother is depressed, helpless or otherwise emotionally absent. The father often uses alcohol to allay his inhibitions before molesting his daughters. Theories have proposed that girls may feel powerless to take active steps to end the abuse for fear of disrupting the family unit.
Psychological symptoms include:
- Deliberate self-harm.
- Sleep disorders.
- Aggressive behaviour.
- Post-traumatic stress disorder.
- Poor concentration.
- Poor performance at school.
- Eating disorders.
- Precocious sexual behaviour with peers.
Associated factors for incest
The increase in the divorce rates may have placed more children at risk than previously. When women begin new relationships, they may unwittingly be putting their children at greater risk for sexual abuse from the men they date. The study by Stroebel et al identified risk factors for father-daughter incest. In the study, father figures were included within the definition of father-daughter. These risk factors included:
- Parents, where the relationship involved verbal or physical fighting, increased the risk of father-daughter incest five-fold.
- Families where father-daughter nudity was accepted increased the risk.
- Homes with a single-parent mother or where divorce/death of the father resulted in another man living at home, tripled the risk.
- Maternal affection was protective - but the likelihood of being a victim of father-daughter incest was highest if a girl's mother never kissed or hugged her.
According to another survey, if the mother remarries, "the stepdaughters are over eight times more at risk of sexual abuse by the stepfathers who reared them than are daughters reared by their biological fathers".
When considering sibling-associated sexual abuse one study looked at male adolescents who had sexually offended against intrafamilial victims (AIV) and compared them to male adolescents who had sexually offended against extrafamilial victims (AEV). A total of 26 independent samples (8 published and 18 unpublished) that compared a total of 2,169 AIV and 2,852 AEV were analysed.
The results of the meta-analysis showed that males who committed AIV presented with greater atypical sexual interests, increased sexual regulation issues, more severe family dysfunction, more extensive childhood maltreatment histories, and greater internalising psychopathology than AEV. Conversely, AEV presented with more indicators of antisociality than AIV.
Other research shows an association between sibling abuse and alcohol consumption.
See the separate Safeguarding Children - Referral and Management of an Abused or At-risk Child article for details as the principles of management are the same.
- The child's welfare is paramount. The child's best interests override other considerations such as confidentiality, consent and the carer's interests.
- Where there is an immediate risk of serious harm to a child, act immediately.
- Share information with other agencies on a "need to know" basis.
- Where possible, and if compatible with the child's best interests:
- Respect the child's views.
- Obtain consent.
- Involve the carers (if the child is competent, this must be with the child's agreement). Do not involve carers if this would compromise the child's safety or evidence.
- Keep full and contemporaneous records.
- Remember other children in the household - are they at risk?
- All doctors have a duty to safeguard children and to ensure follow-on care for the child:
- The non-specialist's role is not to make a definite diagnosis of child abuse but to recognise the possibility and enlist appropriate help.
- The doctor concerned about a child must ensure follow-on care.
- It should be borne in mind that survivors may not experience themselves as victims despite external evidence of abuse, or they may need to reconcile their perception of the sexual relationship as mutual, as opposed to the formal requirement to differentiate between "offender" and "victim".
- The complexity of sibling sexual abuse (SSA) calls for specialist intervention skills, including working with survivor narratives that do not fit the victim/offender dichotomy on one hand and that do not minimise the potentially harsh consequences of SSA on the other.
- Cases of pregnancy by incest tend to present whilst the mother is still of a young age, which can postpone the adolescent's independent access to healthcare, and interfere negatively with abortion assistance as allowed by law.
Further reading and references
Slemaker A, Mundey P, Taylor EK, et al; Barriers to Accessing Treatment Services: Child Victims of Youths with Problematic Sexual Behavior. Int J Environ Res Public Health. 2021 May 1718(10). pii: ijerph18105302. doi: 10.3390/ijerph18105302.
Zoldbrod AP; Sexual Issues in Treating Trauma Survivors. Curr Sex Health Rep. 20157(1):3-11. doi: 10.1007/s11930-014-0034-6.
Krienert JL, Walsh JA; Sibling sexual abuse: an empirical analysis of offender, victim, and event characteristics in National Incident-Based Reporting System (NIBRS) data, 2000-2007. J Child Sex Abus. 2011 Jul-Aug20(4):353-72. doi: 10.1080/10538712.2011.588190.
Carretier E, Lachal J, Franzoni N, et al; Disclosure of Sibling Sexual Abuse by Hospitalized Adolescent Girls: Three Case Reports. Front Psychiatry. 2022 Jan 2512:792012. doi: 10.3389/fpsyt.2021.792012. eCollection 2021.
Stroebel SS, Kuo SY, O'Keefe SL, et al; Risk Factors for Father-Daughter Incest: Data From an Anonymous Computerized Survey. Sex Abuse. 2013 Jan 29.
Carlstedt A, Forsman A, Soderstrom H; Sexual child abuse in a defined Swedish area 1993-97: a population-based survey. Arch Sex Behav. 2001 Oct30(5):483-93.
Cappa C, Jijon I; COVID-19 and violence against children: A review of early studies. Child Abuse Negl. 2021 Jun116(Pt 2):105053. doi: 10.1016/j.chiabu.2021.105053. Epub 2021 Apr 14.
Cyr M, Wright J, McDuff P, et al; Intrafamilial sexual abuse: brother-sister incest does not differ from father-daughter and stepfather-stepdaughter incest. Child Abuse Negl. 2002 Sep26(9):957-73.
Kutz I; Revisiting the lot of the first incestuous family: the biblical origins of shifting the blame on to female family members. BMJ. 2005 Dec 24331(7531):1507-8.
Herman JL; Father-daughter incest, Boston. Harvard University Press, 2000.
Griffee K, Swindell S, O'Keefe SL, et al; Etiological Risk Factors for Sibling Incest: Data From an Anonymous Computer-Assisted Self-Interview. Sex Abuse. 2016 Oct28(7):620-59. doi: 10.1177/1079063214558941. Epub 2014 Nov 27.
Russell DEH; The secret trauma. Incest in the lives of girls and women. Rev Ed, New York: Basic Books, 1999
Martijn FM, Leroux EJ, Babchishin KM, et al; A Meta-analysis Comparing Male Adolescents Who Have Sexually Offended Against Intrafamilial Versus Extrafamilial Victims. Clin Child Fam Psychol Rev. 2020 Dec23(4):529-552. doi: 10.1007/s10567-020-00320-6.
Valle R, Bernabe-Ortiz A, Galvez-Buccollini JA, et al; Intrafamilial and extrafamilial sexual assault and its association with alcohol consumption. Rev Saude Publica. 2018 Nov 1452:86. doi: 10.11606/S1518-8787.2018052000539.
Tener D, Silberstein M; Therapeutic interventions with child survivors of sibling sexual abuse: The professionals' perspective. Child Abuse Negl. 2019 Mar89:192-202. doi: 10.1016/j.chiabu.2019.01.010. Epub 2019 Jan 25.
Bessa MMM, Drezett J, Adami F, et al; Characterization of Adolescent Pregnancy and Legal Abortion in Situations Involving Incest or Sexual Violence by an Unknown Aggressor. Medicina (Kaunas). 2019 Aug 1355(8). pii: medicina55080474. doi: 10.3390/medicina55080474.