Incestuous relationships formulated between siblings are common, though underrepresented in the literature. This paper explores the concept of sibling sexual abuse, the complexity of the social problem, the available literature in the topic, and its devastating effects. Also included are guidelines for treatment for social workers treating families presenting with experiences of sibling sexual abuse.
During the past several decades, various forms of interpersonal family abuse (child abuse, spouse abuse, elder abuse) have been brought out into the open from behind the closed doors of the home. As these various forms of abuse have become known and understood, considerable progress has been made in detecting, treating, and preventing them (Wiehe, 1990).
Child sexual abuse in itself is a devastating act, causing immediate and long-term negative effects on a child victim and family. But what happens when the sexual abuse perpetrator is a family member, specifically a sibling? Family dynamics and relationships are deviated and boundaries are skewed and broken, thus affecting the sibling victim and the rest of the family in ways other than child sexual abuse victims whose perpetrators are non-familial.
Adults are generally assumed to be the perpetrators of child sexual abuse, most likely an adult closely known to the victim. A childís formulation of relationship building is first generated within the family, but the family is also an institution where these relationships and bonds can be easily twisted and manipulated. Unfortunately, familial trust and emotional closeness are often used to lure or trap a child into being sexually abused by a sibling. Because sibling incest thrives on secrecy, the family context is one allowing for ongoing victimization of a sibling with frequent victim access and manipulation of trust through familial bonds. Siblings encounter each other in their lives daily, and this social construct can be used to an offenderís advantage. It has been estimated that 23,000 per million children have been sexually victimized by a sibling (Leder, 1993).
Sibling sexual abuse most often goes unreported and undetected by parents. There is evidence that sibling incest, specifically brother-sister sexual relationships, may be five times as common as father-daughter incest (Wiehe, 1990). Research indicates that there are two age periods when children seem most vulnerable to sexual victimization by a sibling. These are the period between ages six and seven, and the period between ages ten through twelve. But why these periods are the most common, the literature does not speculate.
I believe these periods are likely to be times when abuse most frequently occurs for various possible reasons. At the ages of six through seven, a child is learning social skills and relationship building, and formulating the concepts of trust and respect. A sibling offender may choose this time in a young siblings life to manipulate these learning experiences, utilizing the formulation of respectful and trustful sibling bonds to bribe, trick, and coerce their sibling victim. The second age period where sibling sexual abuse is most likely to occur are ages ten through twelve. This preteen age is a time of extended growth and development, where a childís body and mind is sexually maturing. Sibling offenders may choose to abuse a sibling at this time because the victim is more sexually attractive, sexually aware, sexually capable, and sexually available. These latency age children may be victimized at this age period because their older sibling (possible teenage) is having trouble socializing and adjusting to their own peer group, and may take out these feelings of anger and frustration by abusing their young, weaker sibling.
Sibling sexual abusers are thought be worse than other sexual offenders, whose victims may be inside or outside of the family. Sibling sexual offenders commit more sex crimes for more years, and often practice more intrusive sexual behavior, such as vaginal penetration (Firestone, 1999). Most sibling sexual abuse takes place when the household is asleep when older siblings are asked to baby-sit their younger siblings, leaving the older sibling with power and authority to do what they wish with their victim. Siblings are often left to watch over their younger siblings in their parentís absence, very commonly when parents are at their place of work. This is why brothers and sisters spend more time together during their childhood than with their parents, especially today when nearly sixty percent of mothers with children under age 6, and seventy-five percent of mothers with children aged 6-17, work outside the home (Leder, 1993).
Sibling sexual abuse or sibling incest can include, but is not limited to, unwanted touching, fondling, indecent exposure, attempted penetration, intercourse, rape, and oral or anal sex. In most cases, sexually abusive siblings are three to ten years older than their victims (Wiehe, 1991). Victims, especially younger children, arenít often aware of what is going on when an older sibling uses them for sexual gratification. Only afterward, and very often years later, does the child fell shame or guilt about the incidents when learning more about the meaning of the incident(s).
Like adult sexual abusers, sibling perpetrators often approach their victims as friends, manipulating the sibling bond that harbors feelings of trust, respect, and authority. Also, sibling abuse most often occurs in the context of threats (Wiehe, 1991). Older siblings may threaten their sibling victims with physical harm of parents or professionals are notified of the abuse. Sibling perpetrators pressure, bribe, lie to, or take advantage of their siblings to sexually victimize them in the way they choose. Few children are sexually abused by their siblings once. For most victims, sexual victimization continues from months to years. Abuse increases in intensity, and is often joined by physical and emotional abuse, not only from the perpetrator, but very often from other family members as well. The ongoing trauma of sibling incest usually ends when the sibling is physically old and strong enough to stop the abuse, or upon discovery from a familial or outside source. There are some reported cases, however, where a sibling perpetrator will continue to sexually abuse a sibling through adolescence and into adulthood when the victim has a family and children of their own.
REVIEW OF THE LITERATURE
Sexual activity between siblings is a phenomena that remains poorly understood and infrequently researched. Although the subject of child sexual abuse is receiving increasing attention in the literature, relatively little has been written about sibling incest (Ascherman & Safier, 1990). Numerous authors have suggested that sibling incest is the most common form of incest, although it is the least reported and least written about (Ascherman & Safier, 1990).
Much of the literature addressing sibling incest explains what little is known about sibling sexual abuse and then offers a case vignette to demonstrate how this interfamilial abuse effects the victim, perpetrator, and/or family and treatments utilized, not necessarily generalizing to the greater population. An example of this type of published literature is an article by Ascherman & Safier (1990), which examines a case of an adolescent boy who initiated and maintained sexual activity with his younger sister for a period of years. The article explores the contributing factors and family dynamics involved with this familyís experience with sibling sexual abuse. The authors suggest that when treating families presenting with sibling incest activity, the process of obtaining a detailed family history and assessment is crucial to fully understanding family dynamics, individual psychopathology, and to aid in planning an effective treatment plan. In reviewing this specific case and others like it, the authors found that sibling incest may not always be a situation involving one victim and one aggressor. Both may willingly engage in the behavior in an attempt to cope with unmet needs. In these situations, the authors found that very often the sibling incest occurs in part because parents are distant and nonaffectionate. The authors state:
These authors present an interesting paradigm to sexual contact between child siblings. The idea that children seek out one another to gratify their emotional needs in absence of close parental bonds is not so far fetched. But alternately, the idea that child siblings attend to their sexual needs with one another seems odd, since sexual activity (outside of normal developmental sexual play) is not a childhood behavior. I can see how children may turn to each other for the physical affection that others do not provide for them, such as hugs, caresses, and kisses. But young children learn sexual behaviors and conduct from other, most often adults, and they will not perform advanced sexual behaviors (intercourse, oral sex, etc.) without being taught by an adult.
This theory may ring true for some uncommon cases of sibling sexual abuse, and would possibly be easier to treat since it would require less restructuring of power and control, and more definition of boundaries and roles. I believe most cases of sibling incest are not these types of cases where children seek one another for the sexual gratification of needs.
Other literature surrounding sibling sexual abuse attempts to explore the effects the victimization has had on the abuse survivor. Waldman, Silber, Holmstrom, & Karp (1998) studied groups of adult female incest survivors, one group actively in therapy, and one not. Of the 125 females studied in the two groups, the results suggested that the incest survivor group projected more hostility and had lower feeling of mastery and basic trust than those who were not incest survivors. In addition, it was found that the incest survivors studied showed higher rates of pessimism, and tendencies to view outcomes in extremes.
Another article found in reviewing the literature examines the affect of sibling sexual victimization on adult survivors. Armsworth & Stronck (1999) examined the intergenerational effects of incest on parenting skills, abilities, and attitudes. Results from questionnaires administered to forty women survivors of incest indicated feelings of unbalanced development (parentification), disconnectedness in their lives (geographically or emotionally), and disowned dramas (expression of story). The women survivors also reported growing up in homes that offered little safety, consistency, predictability, and nurturing. Suggestions for future research sited by the authors included a need for both quantitative and qualitative research, as well as exploration in counseling that addresses the needs of this population.
In further review of the literature, articles were reviewed which gave detailed description of specific treatment modules that were effective with families presenting with sibling sexual abuse issues. DiGiorgio-Miller (1998) provided a treatment module for possible use in practice with families experiencing sibling incest. The author begins by suggesting that the practitioner formulate the foundation of treatment in accordance with how the sibling sexual abuse was brought to light. If the parents brought the matter to the authorities, the author states that this will increase the likelihood of reliable parent follow-through with a prevention plan. DiGiorgio-Miller states: "Ötreatment begins with a through assessment of each family members position regarding the disclosure of the abuse" (p. 339). The treatment module suggested in this article also suggests treatment including a safety plan, reevaluated supervision, and eventual reintegration of the offender into the family system.
An interesting article was found in the literature reviewing incest in a different way than most researchers have been willing to explore. Authors Hendrix & Schneider (1999) examined in their article the biosocial theories of incest in relation to innate and societal taboos. The biosocial of theory of incest utilized by the authors also presents a series of assumptions about biosocial learning in families and how the variations in the assumptions can allow for the possibility of incestuous relations. The biosocial theory itself is explained by the authors as a "Öbiological sexual inhibition in the human species, that when broken down by sexual intimacy in the family in childhood, creates inner and outer turmoil, thus creating sexual taboo" (p. 194). Presentation of the familial assumptions are summarized below:
Assumption 2: A personís experiences during early childhood affect that personís mate choices at sexual maturity.
Assumption 3: A personís innate inhibition to sexually acting on impulse is fairly weaker than once thought to be.
Assumption 4: Evolved sexual inhibitions within the family are mostly unilateral than mutual.
Assumption 5: Incest taboos banning parent-child and sibling sex grow out of sexual inhibitions acquired in early childhood.
Finally, in review of the literature, an article was found by Firestone, Bradford, McCoy, Greenburg, Larose, & Curry (1999) exploring recidivism rates in sexual offenders, including incest offenders. 251 offenders were assessed in areas of sexual functioning, hostility, alcohol abuse, psychopathology, cognition, sexual arousal, and criminal offense history. Findings indicated a 6.4% sexual offense recidivism rate for incest offenders, very similarly to projected incest offender recidivism rates. The findings of this study also showed a 12.4% violent offense recidivism rate and a 26.7% criminal offense recidivism rate for offenders participating in the study. Results further indicated that offenders more likely to re-offend were found to have high rates of family alcoholism, violence, and criminality.
The literature presented here is not adequate to best explore the complex realm of sibling sexual abuse. This review of the literature is taken from the available sources of the student, and in my opinion is very lacking and sporadic in its attempts to provide insight and understanding of the problem. Researchers in this area very often pointed out the gap in the literature on this problem, but not one of the authors had written more than one published and available article for review on the topic, furthering the research that they claim is desperately needed. The articles presented in this review most often provide pilot studies, that merely scratch the surface of the problem, with no attempts at replication of studies to strengthen the validity and reliability of the studies therein. Other articles only present authorís opinions of how to treat families who present with sibling sexual abuse, with the authors boastfully providing a case scenario which they successfully treated a family with their treatment module. This is helpful for practitioners if a family presents with similar sibling incest dynamics, but families are monumentally different, and each case will not likely fit into the triumphant mold that the authors suggest as a cure-all for these families.
Research in the field of sibling incest needs to increase, become more widely available, and understandable. This literature review proves that in the field of social work, a widely studied field, there is a glowing gap that needs to be filled since this social problem is large and awareness is increasing.
ITERPRETING THE IMPACT OF INCEST ON CHILDREN
The children are negatively traumatized by sibling sexual abuse and may require help to minimize the effects of their victimization. Children sexually abused by a family member are negatively impacted in many more ways due to the incestuous type of victimization. Explored below are different theoretic aspects that identify how a child is affected by sibling incest.
Incest as Trauma
Child siblings are traumatized by the sexual abuse event(s) and they are affected in many ways. When a child is developing into adolescence and adulthood, erotic interests are shaped and by different social influences and new sexual experiences are "fitted to exist a changing map of sexuality" (Maddock & Larson, 1995). The way the child victim reframes this traumatic event to fit their personal theory will determine the amount and severity of the immediate impact on their lives. If what that child perceives from the sexual contact doesnít fit in their understanding or personal theory, and I donít think it often does, then the child will be greater traumatized by the event.
Trauma is defined here as "an emotionally intense experience that has highly charged emotional impact without an adequate internal explanation, thereby interrupting the childís ongoing adaptation of self" (Maddock & Larson, 1995). The result is severe, overwhelming anxiety out of which behavior problems can arise. Children then interpret the trauma in ways they can understand. They might believe theyíve behaved badly and required punishment. Some children might think that they, for reasons unknown, have been singled out for special love or attention by the sibling. No matter how a child attempts to explain the reasons for the victimization, the better it helps them to cope with the abuse, the better they will adjust to the trauma.
Incest as Loss
Each child victim acts differently in response to the sexual abuse by a sibling, but many responses have certain characteristics in common (Maddock & Larson, 1995). Two primary issues are power/control, and loss and abandonment. Children victimized loose a sense of power and control over their safety, environment, body and other factors that contributed to the abuse experience. Also, child siblings endure great amounts of perceived losses, including: loss of innocence, loss of care and support, loss of child role in family, loss of self-esteem, loss of capacity to trust adults, loss of normal coping mechanisms, and the loss of normal sexual development sequences (Maddock & Larson, 1995).
These losses, along with the manipulation of a childís sense of power and control, contribute to the short and long-term effects of sexual abuse perpetrated on a sibling by a sibling. I think these theories do well to explain what sibling sexual abuse does to a childís emotional capacity and explains why children who endure this type of abuse need specialized treatment and specialized professionals assisting them in the areas outlined here. Child sexual abuse in itself is a complex and devastating social problem which calls for professionals to be highly trained in its causes, effects, and treatments. Sibling sexual abuse calls for significantly advanced professionals who not only understand these concepts of child sexual abuse, but also the additional components that are added when siblings bonds are added to the perpetration.
APPLICATION TO PRACTICE
In reviewing the literature, some treatment models were outlined by authors in the field. None gave specific intervention ideas, formulated through use of research, practice, and basic trial and error, which I felt were useful or practical when working in this area. This lead to my interview with Becky Palmer, MS, Director of Programs and Administration at The Center for Contextual Change, Ltd. in Oak Park, IL. She is a professional currently working with families presenting with sibling incest, and her application of theory, treatment, and personal wisdom added great insight into formulating a treatment guidelines of my own when working with families who have experienced sibling sexual abuse.
The formulation of these treatment guidelines are a conglomeration of many different resources, including the articles outlined in the literature review, books on the topic of incest, and the in-person interview with Becky Palmer, MS. Sources will be recognized when included in my "best practices" treatment guidelines described below.
"Best Practices" Treatment Guidelines when working with Families Presenting with Sibling Incest
Phase 1: Intake Process
How the family is brought to a professional social worker for treatment has great bearing on how well the family will willingly contribute to treatment and is the greatest predictor of a successful outcome (DiGiorgio-Miller, 1998). It is important to examine how the sibling incest was discovered, and how it was brought to light by the authorities. If the parents made the decision to address the matter, then they are likely to take the matter seriously and will support the victim. This is a good sign for the course of treatment because when the parents are the whistle-blower, the victim is supported and the offender is held accountable.
If the sibling sexual abuse is brought to a clinician, and has not yet been reported to the proper authorities, it is encouraged to have the family themselves report the abuse, with the assistance and support of the social work professional (DiGiorgio-Miller, 1998). Social workers are mandated of course to report to the Department of Children and Family Services, but with guidance and help, it is beneficial to the parents of the family to report the abuse to empower the victim and to place consequences on the perpetrator. If the family refuses to report the abuse, even with the clinicianís help, the sexual abuse must be reported, but an obstacle is then present in treatment. Once the social worker reports the abuse and brings forth the investigation that ensues, it enables the family to then blame the practitioner for all the unrest and turmoil that the family will likely go through.
During the intake process, it is stressed by authors Maddock & Larson (1995) that each family memberís "reality" be examined and accepted as meaningful and important to gain the familyís respect. To me, this sounds like the basic social worker theoretical perspective of starting where the client is at. Family members coming to a social worker have already learned to cope in some way to deal with what has happened in their family. Challenging these beliefs and coping mechanisms will likely cause an unnecessary power struggle between the clinician and the clients and will be a difficult obstacle to overcome in treatment efforts.
Intake should also include an immediate formulation of a safety plan. As Becky Palmer stated in her interview, "it is important to insure safety, both inside the office, and outside once the family goes home" (B. Palmer, personal interview, April 12, 2001). Safety might not be difficult to ensure in most families, since the offending sibling may have already been removed from the home. Other families thought require extensive and creative plans to ensure victim safety until the next treatment appointment to address the offending issues at large.
Phase 2: Treatment
Once intake has been accomplished and agreed upon and working safety plan has been enacted, treatment of the family can begin. Authors differ in their belief of where a social work practitioner should being when starting treatment with the family. Some claim is it best to being with addressing issues of power and control, confronting cognitive distortions and role changes in the family. Others believe that the best place to begin is to set boundaries. Of the treatment modules Iíve examined, I believe the next best step is to fully assess the family and the crisis situation the family may present.
It is my experience working with juvenile sex offenders that if there are other crisis situations occurring in a personís life, they will not fully commit and thrive in treatment until they have stabilized and are ready to being a therapeutic relationship. Of course offenders may claim to never be ready for treatment, denying their offending thoughts and behaviors, but family crises can be better addressed and dealt with before progressing into treatment stages. The social work clinician, to better aid family members in their therapeutic process, should address crises in the initial stages of treatment. The family can then better adapt to treatment and focus on creating change while addressing the issue of sibling incest.
In the thorough assessment, an interview should be held with the sexually abusive sibling, checking to see if the offenderís and the victimís stories match. If the offender is in denial about the offense(s) individual treatment should be included in the abusive siblings treatment, to better confront the offender in work with a specialized practitioner who has worked with offenders of this type (B. Palmer, personal interview, April 12, 2001). Sexual abusers of this type will likely undergo treatment in individual therapy in areas such as self-esteem, social skills, impulse control, and healthy sexual patterns of thought (DiGiorgio-Miller, 1998).
Use of the creation of a genogram may be useful in this initial stage of treatment to explore familial patterns and bonds, which will be explored in future stages of treatment. Creating a thorough genogram with the family will likely be a wealthy source of information at a later time.
Once an assessment has been gathered through interviewing all family members and creating a genogram, treatment can progress. Treatment may focus on a variety of aspects present in the family system. Each family will have a varying treatment plan, but the concepts outlined below should be addressed in some fashion in each family presenting with sibling sexual abuse.
The idea of boundaries in a family must be explored in treatment. In cases of sibling sexual abuse, boundaries are blurred and roles are enmeshed. Children become overly dependent on one another for needs and break out of predefined boundaries created in the family. Social work clinicians need to redefine roles in the family, restructuring and reinforcing boundaries, realigning the "broken" system of the family. It is very important that the parents reestablish the power and control in the family, relinquishing it from the perpetrator, by helping the practitioner redefine these roles, and stick to them. Becky Palmer also believes that in this stage of treatment it is important to make it clear to the offending sibling that s/he does not have to behave negatively to gain control or attention from the parents in the family (B. Palmer, personal interview, April 12, 2001).
Lack of Supervision
Parents during this treatment phase must also be confronted by the victim and/or social work practitioner to face what part they played in the sexual abuse experience, in the way of providing less than adequate supervision. Lack of parental involvement on the whole is very often said to be one of the major reasons sibling sexual abuse occurs in families (Maddock & Larson, 1995). Lack of parental involvement leads to the offenderís opportunity to act impulsively and not get caught, or turns child siblings to one another for comfort guidance and affection (DiGiorgio-Miller, 1998). In both cases, distant parents cause a victim to be less likely to disclose the abuse. Parents in this stage of treatment need to understand how their absence or inaccessibility allowed the opportunity for the abuse to take place. Once parents can accept their responsibility in this way, they hopefully will be more willing to be open to their children and accessible to prevent sexual contact in the future.
Stage 3: End of Treatment
Though Becky Palmer in her interview stated that treatment most commonly lasts for about two years, families do usually complete treatment with help of a good strengths-based, patient social work clinician (B. Palmer, personal interview, April 12, 2001). The steps leading up to successful termination are great, and only with careful planning will a family be sure to succeed in stopping future sibling incest situations.
It is common theme in the literature that in this ending stage of treatment the offender be asked to come to a family session and apologize to the victim. Apologies to the parents from the offender may also be given in this session (DiGiorgio-Miller, 1998). Becky Palmer believes in the apology session, but states that it is not a good idea to proceed until the victim agrees to take part in the session without persuasion or confrontation (B. Palmer, personal interview, April 12, 2001).
Becky Palmer believes that a large step in completing treatment, and eventually terminating with the social work clinician, is making sure the offender and his family know and understand the offenderís cycle of abuse. The cycle, created in individual or family treatment, is the key to understanding the offenderís thought and behavioral patterns in the past, and likely the future. With the familyís help, an offender can recognize when he is in his cycle in the future, and hopefully stop from committing another sexual offense (B. Palmer, personal interview, April 12, 2001). In my work with juvenile sex offenders the creation and awareness of the offense cycle was a great tool in use to identify triggers, grooming behaviors, and other thought and behaviors indicating the likelihood of a sex offense to take place.
Another important tool to incorporate into the ending stages of treatment for incestuous families is the formulation of an increased support system. Support systems need to be expanded for families experiencing sibling sexual abuse, for parents, and the children. Because families presenting with sibling sexual assault often feel isolated and "damaged" it is important to have the incestuous family linked to friends, professionals, community members, and others that can break those feelings of helplessness and isolation.
Becky Palmer shocked me when she stated in our interview that most families reunify after experiencing and undergoing treatment for sibling sexual abuse (B. Palmer, personal interview, April 12, 2001). Rejoining a family after experiencing sibling sexual abuse is a long and difficult process, but one that can be done with skilled, patient professionals and families willing to work hard in successful treatment.
To adjust the family to the process of reunification, careful attention must be paid to the victimís readiness and needs. Allowing the offender to have visits with the sibling victim and the rest of the family must be slow and careful. Beginning with short, closely monitored visits with all parties involved ensures the readiness and willingness of the family to start anew. Visits should continue for as long as necessary (months to years), and interactions and feelings should be processed after each visit.
Reunification also requires an increased and carefully formulated safety plan, one that the entire family adheres to, possibly for the rest of the siblingís childhood, adolescence, and early adulthood. The modified safety plan, according to Becky Palmer, may include use of door and window alarms, motion detectors, and/or constant supervision (B. Palmer, personal interview, April 12, 2001).
The final aspect that should be incorporated into treatment termination is the familyís knowledge that they can return to treatment at any time if necessary. By communicating to the family about the treatment process, the social work practitioner should encourage the family to seek professional help if they find themselves in a situation they cannot handle on their own. Leaving the door open for families may decrease the chances that another sex offense will occur, with families knowing where to turn to address grooming/offending behaviors and other issues of family members.
Sibling sexual abuse is one of the most prevalent forms of abuse, but yet one of the least recognized. Offenders sexually abusing their siblings have easier access to their victims, engaging in sexual activities that are more severe, and continuing to sexually abuse for longer periods of time. There is a large gap in the literature exploring incestuous relationships between siblings and effective treatments available to address this social problem. When a sibling sexually victimizes a child, that child is impacted in a variety of ways. Children can experience sibling incest as trauma, impacting their lives in relation to how the sexual assault is reframed to fit their personal theory. Incest can also be experienced as loss, challenging the child to reclaim feelings of acceptance, support, and trust.
Included in this paper are suggested guidelines for social workers working with families presenting with sibling incest for family treatment. Social workers in this area will benefit from following the guidelines presented here, as well as encouraging further studies expanding the literature to allow for better understanding of sibling sexual abuse.
Armsworth, M.W. & Stronck, K. (1999). Intergenerational Effects of Incest on Parenting: Skills, Abilities, and Attitudes. Journal of Counseling and Development, 77 (3), pp. 303-315.
Ascherman, L.I. & Safier, E.J. (1990). Sibling Incest: A Consequence of Individual and Family Dysfunction. Bulletin of the Menniger Clinic, 54 (3), pp. 311-323.
DiGiorgio-Miller, J. (1998). Sibling Incest: Treatment of the Family and the Offender. Child Welfare, 77 (3), pp. 335-347.
Firestone, P., Bradford, J.M., McCoy, M., Greenburg, D.M., Larose, M.R., & Curry, S. (1999). Prediction of Recidivism in Incest Offenders. Journal of Interpersonal Violence, 14 (5), pp. 511-532.
Hendrix, L. & Schneider, M.A. (1999). Assumptions on Sex and Society in the Biosocial Theory of Incest. Cross-Cultural Research, 33 (2), pp. 193-218.
Leder, J.M. (1993). Adult Sibling Rivalry. Psychology Today, 26 (1), pp.56-63.
Maddock, J.W. & Larson, N.R. (1995). Incestuous families: An ecological approach to understanding and treatment. New York: W.W. Norton & Company.
Waldman, T.L., Silber, D.E., Holmstrom, R.W., & Karp, S.A. (1998). Incest Survivors Have Different Personality Characteristics Than Nonassaulted Persons. Journal of Social Behavior and Personality, 13 (3), pp. 437-451.
Wiehe, V.R. (1990). Sibling abuse: Hidden physical, emotional, and sexual trauma. Massachusetts: Lexington Books.
Wiehe, V.R. & Herring, T. (1991). Perilous rivalry: When siblings become abusive. Massachusetts: Lexington Books.