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Why do brothers and sisters experiment? (5 reasons why)

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In this blog post, we are going to discuss why brothers and sisters experiment. We distinguish normative sexual behaviours and problematic sexual behaviours amongst siblings, and also how they can lead to sexual assault and exploitation. At the end of this blog, you will also understand how professionals can help teens and adolescents understand what appropriate sexual behaviours are and how caregivers can help.

Why do brothers and sisters experiment?

One of the most common reasons why they experiment could be because of what they saw on television, or what they may have accidentally seen their parents or other family members do. People as children may experiment with their siblings because they are trying to learn and explore their idea of sexual identity.

Experimenting plays a huge role when it comes to learning about ourselves and our environment. It is commonly referred to as the “trial-and-error” process. Children may start experimenting as a result of curiosity, they are curious about gender and sexually related roles. 

It starts with children looking at each other’s private parts and wanting to explore them through touch. If they’re at a very young age, they hardly go beyond touching. Fondling and touching are the most common activities in all age categories. Although, sometimes it is more than just touching and fondling.

Normal Exploratory behaviour

Brothers and sisters experimenting within certain limits can be considered as normal sexual/exploratory behaviour. Such type includes behaviours that:

  • Happen on the spur of the moment and are intermittent.
  • It is agreed upon and neither of them is objecting to this behaviour.
  • The sole focus of their child play is not sex play and involves other interests and activities.
  • Neither of them feels strongly uncomfortable feelings such as anger, shame, fear, or anxiety.
  • The behaviour is not forced upon either of them
  • Usually decreases with appropriate child-rearing practices and caregiver interventions where the child learns how to stop such behaviour.

What is sex play?

Sex play often takes place amongst children who know each other well, are of the nearly same age and have the same abilities. It hardly ever occurs between children who do not know each other at all. Therefore, making brothers and sisters an example in this case because it often occurs between the same sex and could involve siblings. 

It is a common occurrence in childhood where children may show their private parts to each other and touch them in an exploratory way. Normative sexual behaviours and sex play do not include more adult-like sexual behaviours that go beyond touching. 

Brothers and sisters’ casual experiment which is normative can become problematic when it includes more advanced sex activities, and this may be defined as illegal by family or cultural norms or state/federal laws. It becomes problematic when these experiments and experiences are quite often, one-sided, and coercive. It leads to exploitation and sexual assault. And such sibling assault experiences are hardly ever reported or investigated. 

It may have started as casual sex play and turned into something coercive and one-sided. They might feel vulnerable, confused, insecure, and blame themselves for how things have turned out. It is difficult for a child/adolescent to talk about this with their parents or any other adult figure in their life. They may strongly feel uncomfortable or highly embarrassed, as they believe it is taboo.

Problematic Sexual behaviour

Problematic sexual experiments between brothers and sisters, or siblings/cousins of the same sex may be identified through a continuum – from typical to concerning, to problematic. 

These behaviours can be identified when you notice that these sexual acts occur frequently or more than frequently, there is a gap between the two of them (age-gap, developmental gap, intellectual gap, etc). You may also notice that there are strong/upset feelings, it is forceful by nature and may involve threats or aggression. Problematic sexual behaviours include actions such as:

  • Self-touch or self-stimulation that causes physical harm or damage, is very much excessive and occurs in public even after conducting interventions.
  • Frequently occurring sexual behaviours that include an obsession with nudity, pornography, sexting, covertly looking at others when they are naked, habitually showing private parts to others, etc.
  • Sexually touching, poking, rubbing, or squeezing someone without their permission.
  • Sexual interactions include digital-genital contact, oral-genital contact, involves penetration, etc. These interactions between brothers and sisters or siblings in general are considered to be developmentally inappropriate and illegal.
  • Coercive or aggressive sexual contact, sexual contact with animals, and distributing sexual images through texting.

Such problematic behaviours can lead to sexual exploitation and sexual assault. These problematic behaviours don’t need to be always caused by having been sexually abused. Although, sexual abuse and violence between siblings are more common than people know of or talk about. It is underreported and parents may sometimes not know how to deal with it even after it is reported.

If your sister abuses you, you probably hate your sister.

What is Sibling Sexual Abuse?

Sibling Sexual Abuse (SSA) involves a brother and sister, two sisters or two brothers. The most common form of SSA takes place between older brothers abusing younger sisters. People are generally very close to their siblings and due to the close relationship and physical proximity between siblings, sibling sexual abuse is considered to be an opportunistic form of abuse. 

The problematic behaviours mentioned above are commonly seen in abusive siblings. On the other hand, siblings who are victims or have been abused do not usually disclose their experiences because they fear not being believed, fear upsetting parents, and are confused about their role in the abuse. 

Some common factors that lead to sibling sexual abuse are as follows:

  • An age gap of 4 or more years between the siblings.
  • Coercion and Violence (forced sexual acts).
  • Developmentally inappropriate sexual behaviours.
  • Problematic sexual behaviours.
  • Availability and duration – which refers to siblings living in the same house, therefore, are always physically available to being abused.
  • Intellectual and physical disability
  • Gender gap.

Sibling sexual abuse can often induce trauma-related symptoms such as intrusion, hyper-arousal, disassociation. It also leads to feelings of insecurity, lower self-esteem, mental health and adjustment issues into adulthood, and parenting issues. It may also impact families and their relations with one another. 

Therapeutic interventions, sex education, and seeking help from a professional or someone you trust can help you avoid being sexually exploited, or engaging in problematic sexual experiences between siblings.

Therapeutic interventions and guidelines for caregivers

Educating yourself about sexual habits/practices, appropriate behaviours, and consent is very important. Therapeutic interventions or even interventions provided by care-givers can help you have an understanding of sexual development. Parents and caregivers should seek help with interventions from mental health professionals who know about sexual development, childhood and adolescent development, and research-based interventions. 

While conducting these interventions, mental health professionals often look at environmental conditions of the child or youth, parenting style, family values and attitudes, social factors, etc. Each brother and sister experiment or siblings experiment experience is different. The treatment and intervention may vary from case to case. 

Two major and commonly practised research-based therapies are Trauma-Focused-Cognitive Behavioural Therapy (TF-CBT) and Problematic Sexual Behaviour-Cognitive Behavioural Therapy (PSB-CBT).

Certain guidelines for caregivers include:

  • Parents can get behaviour training to be able to prevent or respond to problematic sexual behaviours and other behaviour related issues.
  • Psychological and emotional changes should be emphasized upon, during the child’s development.
  • Debunking myths and misconceptions regarding problematic sexual behaviours and their implications on the child.
  • Communication about sexual behaviour and development is necessary. Rather than avoiding these topics, healthy communication can help.
  • Supporting their children when they use coping and decision-making skills.

Presenting information on delicate topics like these calmly will help the child understand the concept in a better way and the child will feel less awkward. Children feel easier to seek help when they know they can trust you and talk to you about it openly. 


In this brief guide, we discussed why brothers and sisters experiment, what are normative sexual behaviours and problematic sexual behaviours. We also learned about what is sex play and how sometimes it can turn into sibling sexual abuse. Towards the end, therapeutic interventions were discussed and we gave some guidelines for caregivers to keep in mind when child-rearing practices come into play. Please reach out with any questions or comments about this article or related subject matter.

Frequently Asked Questions (FAQs): Brothers and sisters experimenting

How common is it for brothers and sisters to experiment?

A UK-based study shows that most commonly 10% of males and 15% of females have been involved or have experienced and/or experimented with some type of intimate contact with their siblings. The most common behaviour in such type includes the stroking of genitalia. 

The intimate attraction between siblings or cousins who are related is very uncommon in most cases, due to a hypothesis known as Westermarck Impact, people who are living together through their initial developmental years may become desensitised to each other where sexual interaction is concerned. 

Although, it is also known that family members who are separated at birth may feel intimate attraction, as they have always lived apart.

It is also possible that brothers and sisters who live separate or rarely see each other, may develop such an attraction, and also in the case of step-siblings where the parent is not the same.

Are sisters attracted to their brothers?

There are several cases observed when sisters do feel attracted to their brothers, but this is not always the case. As mentioned above, brothers and sisters sometimes when they live separately, grow apart, and later when they meet there is a chance they may feel attracted towards each other. Sometimes the reason behind this could be that they think they understand each other well because they have similar traits, which may make them believe that they have found their ideal partner.

Why am I sexually attracted to my brother?

Experiencing arousal and desire at a very young age is normal as we humans are sexual beings, (most of the time). Our body is naturally designed to feel such attractions. Brothers are often the first members of the opposite sex that sisters come across, which is why there are chances to develop sexual curiosities about them.

Although, your feelings will not necessarily last a lifetime, and you can get rid of them. You need to become aware of your feelings and let yourself get over them politely in an unhindered manner. 

Can siblings marry?

Marriages amongst cousins are legal in most countries, avunculate marriages are also legal in many countries. But sexual relationships are considered incestuous and taboo or illegal almost universally. Sibling marriages are illegal in most countries around the world, but sometimes siblings do get married, and in society, they are frowned upon as it is considered incest and taboo. Society never accepts such marriages. 

Does incest cause birth defects?

Yes, incest can cause birth defects. Incest or inbreeding in humans can cause an increase in the risk of disorders that are caused by recessive genes. This happens because incest leads to homozygosity, and the offspring can get affected by deleterious traits. The biological fitness of the offspring can be compromised in this case. It also leads to deformities, certain congenital defects, and genetic diseases.


Adler, N. A., & Schutz, J. (1995). Sibling incest offenders. Child Abuse & Neglect19(7), 811-819.

Interventions for children and youth with sexual behavior challenges. (n.d.). VLS.

National center on the sexual behavior of youth. (n.d.). National Center on the Sexual Behavior of Youth.

National center on the sexual behavior of youth. (n.d.). National Center on the Sexual Behavior of Youth.

Stathopoulos, M. (2012). Sibling sexual abuse. Australian Institute of Family Studies.

Tiwari, D. (2019, September 26). I experimented with my brother (5 things to do next). Optimist Minds.

Tiwari, D. (2020, September 16). How common is it for brothers and sisters to experiment? (A guide). PsychReel.

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