I'm usually shorter than my brother

If you have a gut, but especially you, then the risk is that you will be smaller than him, the scientists claim.

Research by David Lawson, from the University of London, conducted on 14,000 families, also showed that children born in crowded families are often lower than average. The author found that if there were 3 siblings, the average child would be 2.5 cm lower than his age.

The team followed the babies born in the 1990s. Each year, the child's height is recorded, along with other development indicators. As a result, having siblings generally affects their development, but their influence is much lighter.

Competition between siblings

Ben Affleck (left) is taller than his brother Casey. (Photo: BBC)

One explanation was that the boys demanded higher care, and also required more parent resources than girls.

"It is well known that children born in a crowded family often learn worse at school, but this study is the first to show that the same is true for height. Overall height is a good indicator for health, " said Dr. Lawson.

"If you are the eldest brother, having more children will not affect your development much, but if you are among the youngest, then you can guess that you will be lower than you."

Marjo-Riitta Jarvelin, a specialist in public health and epidemiology at the Royal College of London, thinks the uterine environment may be an important factor."When women are pregnant many times, they may be heavier and lower blood sugar levels, leading to an effect on the pregnancy in the abdomen."

Experts also speculate that perhaps having more children diluted resources (such as time, money and love) that parents could invest in children.

T. An