The similarities of the child: the same as mom or dad?
What will my baby be like? Will I have daddy's protruding ears?
From the first ultrasound scans, mothers-to-be and fathers-to-be find themselves comparing their profile with the shaded features of their baby in the belly. And the assumptions don't stop there: what will our child's temperament be? Will he be an intelligent child, will he have musical skills, will he be creative? There are so many des that we project on this unborn child and we hope that he can take all the best from us. The truth: we have no say. No matter how many suppositions you can make, no one can predict what a child will look or character.
The appearance of the unborn child cannot be planned
In fact, it all seems simple: an egg and a sperm come together, the cells divide - and the result is a miniature man. (READ ALSO: The woman's cycle. How it works) Yet this act of reproduction presupposes infinite possibilities of combinations between genes. Whether a child will inherit mum's blue eyes or dad's brown eyes, whether he develops a tendency to obesity does not depend on a single gene, but on the combination of several genes.
It follows that at each union of egg and sperm the genes combine in an ever different way and always on the basis of the principle of randomness. Therefore, there can never be two genetically identical people, unless they are homozygous twins. It is certainly known that some features of the hereditary patrimony are "dominant" over others. An example: from the union of two people who have respectively brown eyes and blue eyes, a child with brown eyes will most likely be born, since the brown character is dominant over blue.
Do all children look alike?
Today it is known that inheritance does not strictly follow the laws formulated by Gregor Mendel in 1865. In fact, contrary to what was thought in the past, the inheritance of a characteristic does not depend on a single gene, but on several inserts. Therefore there may be exceptions with respect to the provisions of Mendel's laws. It can therefore happen that some characteristics, for example the protruding ears, “jump” several generations. When the baby is finally born, it all materializes. Parents and all relatives put their heads in the cradle and immediately find all possible similarities: "The dimple on the chin was taken from Mom!", "And this cut of the eyes - all dad!"
The most skeptical will now say: What bullshit! The children all look alike! And some researchers agree with them: according to what was discovered by psychologists at the University of California at San Diego, it makes no sense to say that most children are just like their mother or father. Over 100 people were shown photographs of children of different age groups and asked to match them with three possible mothers or fathers. The result: for only a part of the one-year-olds the people interviewed were able to establish unique similarities - and precisely with the father!
It's all her dad!
It is possible that this is linked to evolution, US researchers speculate: in fact, while the mother always knows that the child is actually hers, the father can never be really sure. However, if he recognizes the features of his physiognomy in the little one, he can experience fatherhood in a more intense way.
According to the Californian study, every child looks no more like his parents than he does any other pair of parents chosen at random. This assertion sounds perhaps less shocking when you consider that not only the parents contribute to the child's genetic makeup, but the entire host of ancestors, whose chromosomes have continued to combine over the centuries.
Character: inherited or acquired?
At least to the same extent that they are interested in outward appearance, parents would like to know what "inner values" they may have passed on to their children: their intelligence, their personality, their abilities. For over 150 years, human geneticists, biologists, psychologists and behavioral geneticists have tried to answer this question. More and more genes are being identified and their function identified. More and more studies conducted on homozygous and heterozygous twins, as well as on adoptive families, are slowly trying to shed light on the mystery. However, a certain answer does not yet exist. In fact, there are too many contradictions between the individual facts acquired. Since the beginning of research on heredity, opinions continue to fluctuate between opposite extremes. One day it is said: "Only the environment forms the personality", the next day: "Everything is inherited".
Today, the most accredited scholars have agreed on a rule of 50 and 50. The most recent studies show that a person's intelligence has a genetic basis for about 40%, while the remaining 60% is formed due to environmental factors (therefore playmates, brothers and sisters, events that affect growth). A person therefore does not come into the world as a finite and immutable being, but on the contrary possesses a high potential for development.
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Predisposition is not everything
This concerns any aspect of life: a child who has inherited a certain weakness in reading and writing from his parents can still become a bookworm if, for example, through frequent reading aloud his teacher is able to transmit the pleasure of reading to him. . However, not everything is possible: a child born without any musical talent will probably never become a second Mozart or Beethoven. Conversely, even the greatest (musical) predisposition serves something only if it is recognized and exploited promptly.
Is obesity hereditary?
Scholars disagree on how hereditary the tendency to gain weight or obesity is. No one doubts that there is a hereditary component, but it is not clear whether the risk of gaining weight is 30, 50 or 70%.
In favor of the hypothesis of a strong social influence, the fact that the number of fat people has not increased slowly and uniformly over the course of several centuries, but rather suddenly over the last 10-20 years. Children eat too much, sit for too long in front of the television or computer, do little movement. This has nothing to do with genes. And even if someone has a predisposition for obesity, they don't automatically develop this condition - as long as they eat plenty of fruit and vegetables, don't go to McDonald's, and exercise a lot.
Genes and the environment
At certain stages of life, genes and the environment play a fundamental, albeit different, role. Collaborators of London-based behavioral geneticist Robert Plomin found that families in the first two to three years of a child's life greatly influence their mental development. Once you reach school age, genes take over.
The reason: between the ages of five and six, children are so autonomous that they seek environmental conditions suited to their predispositions. For example, a sporty child during the gym class will check how good he is at throwing or jumping. Growing up he will be able to choose friendships and leisure activities that allow him to develop his predispositions. Always starting from the assumption that the parents do not hinder his inclinations.
Each person is one of a kind
Even in the matter of personality, scholars are looking for the genes possibly responsible for certain character traits. Self-awareness, sociability, scrupulousness - are these and other characteristics passed on to children by their parents?
Up to 60%, researchers say, and regardless of what characteristics it is. In fact, for all of them the probability of hereditary transmission is the same. However, there is a fact that all scientific studies and discoveries cannot change: each person is unique in her gender. Although the human genome has already been completely decoded, a person's development can never really be controlled - at least one can learn more about it. Therefore the futuristic horror scenarios according to which it will soon be possible to "make up" your child by yourself, giving him all the desired characteristics, will remain pure science fiction in the future as well.
Heike Wolf, doctor in behavioral psychology and genetics, holder of the chair of differential psychology at the University of the Saarland in Saarbrücken;
Babette Heye, PhD in Human Genetics, Rechts der Isar Clinic of the Technical University of Munich, Institute of Human Genetics