Twins and School

In many primary schools in the Netherlands twins are being placed in separate classrooms. Most schools have written or unwritten rules that mandate this because teachers think that this is in the best interest of the children. However, recent studies have shown that non-separated twins perform even better at school. Schools should have a more flexible attitude towards twins and discuss the school placement with the parents of the twins.

Max and Porter

Max and Porter


Results of twin studies

In recent years, several scientific studies have looked at the effect of separating twins at school on school performance and behavior (Van Leeuwen, 2005; Webbink, 2007; Polderman, 2010). The main conclusions of these studies were:

Entering primary school (age 5):

  • Separated twins generally show more internalizing problems (such as anxiety and feelings of insecurity) compared to non-separated twins.
  • The school performances of non-separated twins are generally higher than the school performances of separated twins.

By the end of primary school (age 12):

  • There are no differences in levels of behavioural problems (internalizing nor externalizing) between separated and non-separated twins.
  • There is no difference in school performance between separated and non-separated twins.

(for more detailed information on these studies, please have a look at


This means that, looking at the school performances and behavioural problems of twin children, it seems that keeping twins together when they enter primary school generally has at least a shorter term positive influence on the development of the children, both academically and emotionally.

Jim and Sam made their start at primary school at the age of 4. The school wanted to place the boys in separate classrooms, but at the request of their parents they agreed to make an exception. The boys were allowed to start in the same classroom, so they could get used to school together. After the first bank holiday Jim and Sam are being separated. According to the teacher; “they really cling together, so it would be better if they are separated and learn to cope on their own. Just like singletons”. The parents don’t agree, but school goes ahead anyway. Because of their twin policy.

Sam does not seem to suffer much from the separation. He mingles easily with the children in his classroom and does well academically. This is in stark contrast with Jim, who exhibits fearful behavior: he does not seek contact with other children and has suffered from psychosomatic problems such as headaches, pain in his stomach and wetting his pants. Besides that, Jim also scored low on all tests measuring math and reading skills. The teacher advises the parents to see a psychologist because she thinks that Jim is autistic. After extensive research (psychological examination and the Wechsler IQ test for children) the psychologist concludes that Jim has an average level of intelligence. A developmental disorder such as autism is out of the question. According to the psychologist, the psychosocial problems of Jim are probably connected to the separation at school, since Jim only shows this behavior in the school situation. Based on interviews with Jim and Sam, their teachers and their parents the psychologist advises the school to place Jim and Sam back together again.


How twins develop

Most teachers have little knowledge about the development of twins. The special relationship between twin children is rarely acknowledged. Problems related to the separation of twin children at school are often being associated with autism. Parents of twins complain that their opinion about what is in the best interest of their children isn’t taken into account. Teachers tend to think that they have all the expertise at school. Parents need to step back, although they feel the need to have a say in what’s good for their children.

Teachers think that separating twins at school is beneficial for their personal development. But what is often overlooked is that the development of twins children differs from that of singletons. Most twins show diffferences in their language, personal, social and emotional development. Therefore, standards such as those used at school are not always suitable for behavior and performance assessment for twins.


Language Development

Compared with singletons twins generally start to talk later and during the first years of their lives they have a smaller vocabulary and their phrases are shorter and less complex. In addition, 40 percent of twins exibit some form of autonomous language (a private language between them). Twins with large language deficiencies can benefit from additional support (Thorpe et al, 2003).

Tip: Study both language production and language comprehension. For most twins, the language comprehension is much better developed than the language production.

The idea that a separation at school ‘forces’ the children to talk, does not always give the desired result. Especially for twins with a particular close bond, a forced separation can have traumatic effects. The language development can stagnate if the kids miss each other too much, sometimes even regressing to the point where the twins stop talking completely.

Tip: Use a role model: encourage a verbally strong classmate to play with the twins to stimulate their language development.


Social and emotional development

The situation in which twin children grow up differs from that of singletons. During the frist years of their lives most twins spend all their time together. This makes them somewhat socially privileged. Compared with singletons, most twins can play together with other children very well. They have learned to share, discuss, consider one anothers needs and wait their turn.At the same time most twins are strongly focused on each other. They are less likely to seek contact with other children, because there is no need to. This does not make them less capable of playing with other children. But because they largely fulfill each others needs, twins tend to stick together.

Tip: Encourage twin children to mingle with other children.

Growing up as twins has also some disadvantages. The comparison and competition between twins is many times stronger than between ordinary siblings. Dominance, power struggles and rivalries can play a major role in a twin family situation. To what extent these things play a role, can vary between twins and differ per situation. While one twin can be the dominant one at home, the other twin can have this role at school.

Tip: Assist twins to properly assert themselves: a dominant child must learn to give more space to the other and a docile child must learn to be more in the limelight.

In some extreme situations twins argue excessively. If that is the case it can be better to separate the twins at school.


Stand on their own two feet

Twins have a special relationship with each other. During the first years of their lives they have been close together. As the grow older they need to separate from each other. Singletons also need to separate from their parents in order to learn and stand on their own two feet. But for twins this is a more complex process, because they need to learn to separate from each other as well. Most twins are not completely separated by the time they enter primary school. They may still need each other for emotional support or have difficulties in saying goodbye to their parents.

Tip: Allow twin children to sit next to each other whenever they feel like it.

Twins should get enough space to separate from each other in their own way. Forcing their separation can lead to behavioral problems. This behavior can be misinterpreted, where some teachers even advise parents of twins to ask for psychological help (see the example at the beginning of this article).


Together or apart?

For parents of twins it can be difficult to determine whether their children would be better of placed in the same or different classrooms. On one hand it feels unnatural to haved them separated at school, but on the other hand, parents fear that their children’s development is hindered when they share the same classroom.

There are many considerations when we think about separation. The discussion should focus on the question whether the twins can support each other at school. Does that mean that twins should stay together, so they can help each other out? Or are they better off being separated, so they can learn to cope with problem situations?


All twins are different

It is important to realize that all twins are different. Also every child is different. What can be a good reason for one child to stay together at school, could meanwhile be a good enough reaon for the other one to get separated.

Here is a summary of the main arguments that play a role:

  • Twins keep an eye on each other. This has to do with loyalty. For most twin children the presence of the other means safety. Sometimes their functioning in the classroom can be hindered, if the children constantly keep an eye on each other.
  • Twins are being compared. If twins share the same classroom, there will be more comparisons. By the teacher, by their classmates and by themselves. This can have a stimulating effect, for it can encourage twins to work harder. But if one child is always performing better, it can cause negative feelings such as insecurity for the other child.
  • Twins have their own story. Twin children will gain different experiences. They are two different children with their own character, so they will react differently to their environment. Even if they share the same environment. So twins will always have their own story, whether they are in separate classrooms or not.
  • Twins make their own friends. Twins placed in different classrooms will obviously play with other children. If twins share the same classroom, they will both interact with other children and with each other. For the majority of the twins the presence of the other twin does not prevent friendships with other children. In very few cases twins get isolated within the group. But remember, most twin children are best friends.
  • Twins seek support from each other as they feel insecure. At school there can be situations that makes certain children feel unsafe, for example if there is a substitute teacher. It can be comforting if the children can find support from each other.
  • Twins are loyal to each other and they help each other when needed. The loyalty between twins is generally stronger than the mutual loyalty between friends. Twins can feel responsible for each other and feel the need to help each other solve problems. This can be both an advantage or a disadvantage.
  • Purely practical: drop off and pick up. It makes it much easier and less stressfull for the parents if the children share the same classroom. The drop off and pick up from school runs less chaotic and there is more time and attention for the children in the classroom. For school activities in which parents are invited or needed, it is also much easier if the children are together.


Separating twins requires careful consideration and consultation with parents. The needs of the children should be considered carefully, both at individual level and from the point of view of their twinship.

When in doubt, I highly recommend to have twin children start together. Just give them a chance. If it doesn’t work out, you can always decide to have the children separated later on. Also, decisions in this area should never be irreversible. Sometimes, things work out different than expected. Flexibility is the keyword for both parents and teachers.


Leeuwen, M. van, e.a. (2005). Effects of twin separation in primary school. Twin Res Hum Genet. Volume 8, Number 4, pp. 384–391

Polderman, T.J.C,. e.a. (2010). No effect of classroom sharing on educational achievement in twins: a prospective, longitudinal cohort study. J Epidemiol Community Health

Thorpe, K. e.a. (2003). Twins as a natural experiment to study the cause of mild language delay: II: Family interaction risk factors. Journal of child psychology and psychiatry, 44-3, 342-355.

Webbink, D. e.a. (2007). Does sharing the same classroom in school improve cognitive abilities of twins? Twin Res Hum Genet. Volume 10 Number 4 pp. 573–58


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