How Common Is It for Brothers and Sisters to Experiment? 2024 Statistics

Let’s dive deep into these facts on sexual exploration between siblings, how common it is for brothers and sisters to experiment, and its long-term impact.

how common is it for brothers and sisters to experiment

Children are naturally curious about everything, including their reproductive organs. They’re especially curious about the opposite sex, and this curiosity only intensifies during adolescence. 

While it is natural for children to be curious, there is a very fine line between healthy exploration and traumatic abuse.

Different sources debate the possibility of consent between children, as well as the factors and conditions that turn innocent acts into abusive acts. 

Our research covers the different theories on sexual exploration between siblings, its prevalence in society, its long-term impacts on participants and victims, and more. 

Here are some highlights from our research:

  • 13,013 cases of sibling sexual abuse were reported in the National Incident-Based Reporting System from 2000 to 2007.
  • One study in 1980 found that 15% of females and 10% of males reported having some kind of sexual experience with a sibling. 
  • A 1989 study found that 5% of participants had a sexual encounter with a sibling prior to the age of 13, and 12% reported having both a sibling and nonsibling sexual experience.
  • One study found that 100% of brother-abused women experienced depression, and 56% experienced substance abuse. 
  • Research suggests that we subconsciously find our relatives more attractive than strangers but consciously find them aversive. 

What Is Sexual Experimentation Between Siblings?

Some of us have experienced it, and some of us find the idea foreign and/or repulsive. Sexual experimentation between siblings can come in many forms and from many causes, but these data points give the textbook definition:

  • In recent years, there has been an increase in instances (or at least reports) of siblings experimenting sexually.

Possible causes include media exposure, increases in sexual web content, and the general breakdown of the family structure. As culture becomes more individualistic, family members drift apart. 

Sexual activity between siblings is also referred to as incest.

Incest can be defined as sexual activity with a person in the immediate family, also called intrafamilial sexual abuse.

Sources: Psych Reel, Patient

Why Do Brothers and Sisters Experiment?

Children imitate what they see and explore what they don’t understand. So when exposed to sexual content, whether it be through media or real life, they will inevitably seek answers. 

Because so few parents are willing to explain sex to their kids, they often take it upon themselves to learn. 

  • Common reasons for sibling sexual experimentation include exposure to content on television or the internet or what children accidentally witness adult family members do.
  • Children may start experimenting due to curiosity – they are generally curious about gender and sexual roles and are not often educated sufficiently.
  • Sibling sexual experimentation begins with seeing each other’s private parts and wanting to explore them through touch. At very young ages, they rarely go beyond touching.

Across all ages, fondling and touching are the most common activities. However, sometimes it goes beyond this. 

Source: Half Full Not Empty

Is It Normal for Siblings to Experiment Sexually?

Kids have a certain level of innocent curiosity that can make taboo things more normal. However, sexual encounters between children are only normal when responsible adults acknowledge, explain, and intervene. 

It’s not wrong that children want to know and try these things; it’s wrong when adults allow it to escalate to a harmful level. 

These data points illustrate the normalcy of sibling sexual exploration. 

Some research indicates that sibling sexual experiences among children are relatively common.

Research suggests these experiences are the least reported and least investigated sexual behaviors among adolescents. 

Females may be more vulnerable to exploitative sibling sexual experiences than males. 

Within certain limits, brothers and sisters experimenting can be considered normal, though a caretaker should interveneThe following criteria describe normal exploration: 

  • Intermittent experiences that happen in the spur of the moment.
  • Activity that is agreed upon and neither one objects to the behavior. 
  • The sole focus of the exploration is not sex play and involves other interests or activities. 
  • Neither individual feels strongly uncomfortable feelings like anger, shame, fear, or anxiety. 
  • The behavior is not forced upon either of them. 
  • The behavior decreases with appropriate parenting practices and caregiver intervention that teach the child how to stop.

Sources: This Is Guernsey, Half Full Not Empty

Psychological Characteristics of Brother-Sister Experimentation

Experimentation between siblings can come from innocent curiosity or the confusing sexuality of adolescence. In some cases, there can be a sexual attraction present, and many of these cases are categorized as abusive. 

At younger ages, this experimentation appears to be more innocent. However, through adolescence, it can become more harmful. 

Here are some data points on how and why sibling experimentation may occur:

The intimate attraction between people who are related is uncommon. It is hypothesized that people living together through formative years become desensitized to each other in terms of sexual attraction.

This hypothesis is known as the Westermarck impact. 

Westmarckian theory postulates that the non-conscious presentation of a relative triggers an automatic mental system that makes them seem sexually unattractive.

One study asked 74 students to rate the sexual attractiveness of strangers’ faces with the following results:

The study
Half the students were given a subliminal presentation of a family member, and half were not.
Those subliminally presented with their own family members rated the faces as more attractive than the other group. 
In a second study, half the students were shown faces morphed to resemble their own faces. 
This half rated the faces as more attractive than the other group, which was shown unaltered faces. 
In a third study, half the students were shown unaltered faces but were told that the faces had been morphed to resemble their own.
They rated these faces less attractive than the group shown unaltered faces. 

These studies suggest that we subconsciously find our relatives more sexually attractive but consciously decide that they are less sexually attractive

One study found that 15% of females and 10% of males reported some type of sexual experience with a sibling.

One-quarter of the experiences were described as exploitative due to the use of force or a large age gap between the siblings. 

Females were more likely than males to both be exploited and to feel bad about it. 

For males and females, very few participants had ever told anyone about their experience. 

Females who reported sibling sexual experiences, whether the experiences were positive or negative, had significantly higher levels of current sexual activity. 

  • Those with positive sibling sexual experiences after the age of 9 had more sexual self-esteem. 
  • Experiences with much older siblings that took place before the age of 9 were associated with lower self-esteem and no increase in current sexual activity. 

Brothers and sisters, in some cases, may experiment because they meet infrequently or have different parents – i.e., stepbrothers and stepsisters.

Genetic Sexual Attraction is the term for when siblings become attracted to each other after a long period of separation during their formative years.

In adoption situations, this can affect families who were separated very early in the adopted child’s life. 

There is no clear consensus on when it is possible for children to have consensual sexual interaction with each other, especially as early as 10, 11, or 12 years old.

Adolescence is typically divided into early (age 10 to 13), middle (age 14 to 16), and late (age 17 to 19) stages, where it is normal to experience physical, hormonal, and emotional changes that spark sexual interest and experimentation.

Sources: Psych Reel, Research Digest, Archives of Sexual Behavior, This Is Guernsey, Optimist Minds

Sex Play Among Siblings

Sibling incest is more common than incest between parents or other relatives and children. In addition, the negative impacts of sibling sex play seem to increase with the age gap. 

When one sibling is much older, the dynamic becomes more exploitative and more harmful.

One study found that sexual penetration was much more frequent (70.8%) with sibling incest than it was in stepfather (27.3%) or father (34.8%) incest cases.

One 1989 study of 526 undergraduate students found that:

Reported having had only a sibling sexual encounter. 
Reported having had both a sibling and nonsibling sexual experience in childhood. 
Reported only having a nonsibling sexual experience. 
Reported no sexual experience with another child before the age of 13. 

The study concluded that early childhood sexual experiences with similar-aged siblings did not have a significant impact on adult sexual adjustment. 

A 1989 study of 831 children under the age of 14 who were evaluated for sexual assault complaints found the following data:

Incest case
Cases of cousin incest
Cases of sibling incest
54 male cousins had abused
Brothers had abused
54 male cousins had abused
Brothers had abused

79% of the perpetrators were at least 5 years older than their victims. 

Sources: Child Abuse & Neglect, Child Abuse & Neglect, Archives of Sexual Behavior

What Is Sibling Sexual Abuse?

When sexual exploration between siblings becomes harmful, forced, exploitative, or negative in any way, it becomes sibling sexual abuse. 

It’s the most common form of incestual abuse for children and is most commonly perpetrated by older brothers toward younger siblings. 

Sibling sexual abuse (SSA) involves a brother and sister, two sisters, or two brothers. The most common scenario is with older brothers abusing younger sisters.

One study of 62 female incest victims found that 23% were sexually abused by a brother, and about 24% were abused by a father.

Women Experienced
Substance Abuse
Eating Disorders
Women Experienced
Substance Abuse
Eating Disorders

Common factors leading to SSA are as follows:

  • An age gap of 4+ years between siblings. 
  • Coercion and violence or the threat of violence. 
  • Developmentally inappropriate sexual behaviors. 
  • Problematic sexual behaviors.
  • Availability and duration – siblings living together are physically available for abuse. 
  • Intellectual and/or physical disability.
  • Different genders. 

Sources: Half Full Not Empty, Child Abuse & Neglect

How Common Is Sibling Sexual Abuse?

We’ve said it already, but we’ll reiterate – sibling sexual abuse is the most common form of incestual child abuse. 

The numbers vary, but recent studies into the phenomenon have shed more light on just how prevalent SSA is. Here are the statistics we gathered:

13,013 cases of sibling sexual abuse were reported in the National Incident-Based Reporting System from 2000 to 2007.

SSA may be the most common type of incestual sexual abuse. 

SSA has been documented as being five times more common than father/stepfather abuse.

Though trivialized as normal sexual exploration, sibling sexual abuse is linked to psychosocial and/or psychosexual dysfunction.

An Australian sample found that 57% of victims of incestual abuse were experiencing SSA. 

A study of 194 child sexual abuse victims in Florida found that half of their victims had experienced SSA. 

8 years of National Incident-Based Reporting System data found the following statistics on SSA:

National Incident-Based Reporting System Data
SSA offenders were male.
SSA offenders were older than their victims. 
SSA offenders were over the age of 12. 
5.5 years
The average age gap between offenders and victims
Cases involved male offenders and female victims.
Cases involved male offenders and male victims. 
Cases involved multiple offenders. 
55% of cases
The most common type of SSA was forcible fondling. 
SSA incidents occurred in the victim’s home. 
Cases involved some kind of weapon, though in most cases, these were “personal weapons” – i.e., the offender’s hands or feet.
Overall cases involved traditional weapons.  

Sources: Journal of Child Sexual Abuse, Frontiers in Psychiatry, Patient, Journal of Child Sexual Abuse

What Should You Do If You Have Experimented With Your Sibling?

Sexual experimentation can be confusing and cause several uncomfortable feelings. These feelings can be magnified when it takes place with a sibling that you grew up with. 

The most important thing to remember is that this has happened to millions of people and that your feelings about your experience are valid. Shame, guilt, fear, and confusion are common. 

An individual may feel positively or negatively about their experience, but it is always helpful to seek guidance from a trusted counselor or a counseling resource. 

If you are hurt or feel like you are in danger, contact the National Sexual Assault Hotline and talk to a confidential counselor for support, advice, and resources – or if you just need someone to listen. 

If you have experimented with your brother or sister consensually and feel bad or confused about the experience, try the following steps:

  • If you no longer wish to do it, make it clear to your sibling that you are uncomfortable with the act. 
  • If your sibling persists, get distance from them and talk to an adult you trust who can intervene. 
  • Intimate relationships can be dangerous when your body and mind are still developing; try to gain distance from the relationship either way. 
  • Seek education from an adult, teacher, doctor, or relative you trust so that you can make informed decisions about your health and sexuality. 
  • If you feel guilty or afraid about what you have done, try to talk to your parents. If you cannot talk to your parents, try to consult a therapist. They will not tell your parents what you have told them and can give you educated advice. 

Source: Psych Reel

FAQs About Brother-Sister Sexual Experimentation

A few big questions are commonly asked about brother-sister experimentation, and we’ve done the research to answer them for you here:

Is experimenting with your brother or sister always bad?

One study found that:


However, there is a real danger of long-term psychological consequences such as eating disorders, low self-esteem, suicide, and more; sexuality is best explored outside of your family. 

Source: Journal of Child Sexual Abuse

Can a brother and sister make a child?

Siblings can have children together, but the lack of genetic diversity in their children creates a greater risk for hereditary disease or developmental problems. 

Source: This Is Guernsey

Can siblings be attracted to each other?

It’s hypothesized that an automatic mental process makes our relatives sexually aversive to us. However, we need to be consciously aware that they are our relatives. If you didn’t grow up around relatives or aren’t aware that you’re related, sexual attraction is possible. 

Source: Research Digest


Siblings have a unique developmental relationship that can’t be replaced by friends, parents, or partners. They bond through a shared environment of growth and curiosity. If this curiosity becomes sexual, it can be mitigated and clarified with the right guidance. 

However, this exploration can easily become abusive and exploitative if left unsupervised. It is the most common form of incest and has largely been underreported and underinvestigated until recent years. 

When sibling sexual exploration turns into sibling sexual abuse, it can create long-term problems for the victims. For women, this often manifests in suicidal thoughts, low self-esteem, substance abuse, eating disorders, and more. For male victims, it is so underreported that researchers are still trying to understand the long-term effects. 

The saddest part about the common transformation from innocent sexual curiosity to child sexual abuse is that it is both preventable and unnecessary. Parents could save their children years of psychological torment by paying attention, acknowledging the behavior, and simply talking to their children about sexuality

The questions and curiosities that children have do not go away when we ignore them. Parents don’t ignore their child’s questions about busy streets and then wait for them to get hurt – so why do they so often do the same about sex?

Dainis Graveris

Dainis Graveris

Over last 4 years Dainis have helped millions of people through his advice on this site (200+ guides and 1M+ visits/monthly). His work & advice has appeared on sites like: Healthline, Vice, Cosmopolitan, Men's Health, WomensHealthMag, MindBodyGreen & more. Read More.

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