Siblings: how brothers and sisters affect our lives

1. They shape your character.

It is widely believed that birth order affects personality: the first-born, say, mature faster and become leaders more often, and the younger ones are everyone’s favorites and darlings of the family. But these theories are not backed by science. Researchers have not yet been able to find any character traits that clearly correspond to the order of birth.

On the other hand, there is evidence that you and your sibling can influence each other. Psychologists have described the phenomenon of “disidentification” – this is when siblings (usually close in age) consciously or unconsciously strive not to be like each other, each creating their own, separate identity. This is manifested in the development of each of the brothers and sisters of their specific abilities and character traits, in their passion for something special.

For example, if your older sister is doing great in sports, you are more likely to focus on intellectual pursuits. If your brother is a homebody and quiet, you might make an effort to become more outgoing and outgoing. This “division of labor” occurs more often in families with two children, and in families with many children – between siblings of the same sex.

2. They change your eating habits

It is well known that obesity can be inherited, but studies show that brothers and sisters play an important role in shaping our complexion in their own way.

Economists from Duke University found that in families in which the oldest child is obese, the youngest child is five times more likely to become obese (regardless of whether their parents have weight problems)¹. The authors partly explain this by the fact that younger siblings tend to copy the eating habits and lifestyles of their older siblings.

The age difference also matters. A study by Michigan State University pediatrician Julia Lumeng, MD, and her colleagues found that children who were given a younger sibling by their parents before they were 5 years old were significantly less likely to become overweight later on.². The reason, in general, lies on the surface: next to other children who are close in age, they grow much more mobile.

3. They are your first teachers

Siblings help each other navigate different social situations. To begin with, their daily communication is a great practice of understanding the thoughts and feelings of another person. Strong bonds between siblings help them communicate successfully with their peers at school.

And the presence of a brother in a girl or vice versa, a sister in a boy gives more opportunities for dating and romantic meetings with peers of the opposite sex. In a now classic 1983 study by noted psychologist William Ickes, college students who had a sibling of the opposite sex found it quicker and easier to strike up a conversation with a potential romantic partner. For their success, they, of course, should thank their older brother or sister.

And, by the way, the presence of a receptive, understanding brother or sister contributes to the formation of cognitive abilities. A study by Canadian psychologists published in the journal Pediatrics in February 2014, on the one hand, confirmed a well-known fact: children in large families tend to have a low vocabulary (perhaps because parents have less time to communicate with each child individually ).

However, it turned out that this does not apply to those children who are lucky enough to have “cognitively sensitive” older brothers and sisters, who are ready to simplify their speech and clarify incomprehensible words to the younger ones.

4. They can save your marriage

Believe it or not, men and women who grow up in large families are less likely to get divorced. A massive 40-year study by Ohio State University researchers found that each of your siblings reduces your risk of divorce by 2%.³ Let’s say if there were five more children in the family besides you, your chances of parting with a partner are less by as much as 10%.

“When several children grow up in the same house at once, they are forced to learn to find a common language with each other, and this, apparently, makes them more flexible and tolerant in marital relations,” commented co-author of the study, sociologist Donna Bobbit-Zeher.

5. They make you more likely to experience depression.

Although quarrels and skirmishes are so natural for brothers and sisters, years of rivalry can have serious consequences for their health. Researchers from the University of Missouri found that siblings who often argued about who was right and who was wrong had higher levels of depression after a year.

And those who constantly fought for personal space had a higher risk of developing anxiety and low self-esteem. While this study included adolescents between the ages of 12 and 15, other research suggests that problematic sibling relationships increase the risk of experiencing depression and taking psychotropic drugs in adulthood.

6. They make you happier

Conversely, warm, conflict-free relationships with brothers and sisters promise us solid bonuses. Close family contacts are often associated with lower levels of loneliness and depression, and higher levels of self-esteem. Even in early childhood, siblings look to their siblings for support and comfort in difficult situations.

This fraternal mutual assistance remains the main support for adults in difficult life circumstances, including such critical ones as the illness or death of parents. As shown by a long-term study by Swedish scientists who interviewed 80-year-old residents of the Gerontological Center in Lund (Sweden), those who consider their relationship with their brothers and sisters happy, and generally feel more satisfied with life.

1. M. Harding et al. «Within-family obesity associations: Evaluation of parent, child, and sibling relationships», The American Journal of Preventive Medicine, 47, 2014.

2. «If Younger Sibling Arrives Before 1st Grade, Kids Less Likely to Be Obese: Study» HealthDay News, March 11, 2016.

3. «Having More Siblings May Help Save Your Marriage» HealthDay News, August 13, 2013.