What a genetic combination is, it's very difficult to say. People are trying to predict, but nature and genetics are just doing their job. In the formation of a combination of the genetic characteristics of the child, strong (dominant) and weak (recessive) genes take part. Strong genetic features include dark hair, as well as curly; brown, green or brown-green eyes; dark skin; baldness in men; positive Rh factor; II, III and IV blood groups and other signs. They also include a large nose, a nose with a hump, large ears, pouting lips, a high forehead, a strong chin and other "outstanding" features of appearance. The weak genetic features include red, light, straight hair; gray, blue eyes; bright skin; baldness in women; negative Rh factor; I blood type and other signs. Dominant and recessive genes are also responsible for predisposition to certain diseases.
So, the child gets a set of dominant genes. For example, a child can have a daddy's dark hair color, mother's brown eyes, grandmother's thick straight hair and grandfather's "stubborn" chin. How does the order of inheritance of genes look like? Each person has two genes - from the mother, and from the father. For example, a husband and wife have brown eyes, but each of them also has a gene responsible for the blue eye color inherited from parents. In 75% of cases this pair will have a brown-eyed child, and in 25% - blue-eyed. But sometimes, light-eyed parents are born dark-eyed children, since the parents had a gene responsible for the dark color of the eyes, which was transmitted to them, in turn, from their parents, but did not appear as dominant. In other words, it is more and more complicated and much more complicated than simply the struggle of dominant and recessive genes.
The external data of the person are the result of mixing of several genes, therefore the result can not always be predicted. Let's give another example with the color of the hair. For example, a man has a dominant gene for dark hair, and a woman has a recessive gene for blond hair. Their child, most likely, will have a dark shade of hair. And when this child grows up, his own children can have blonde hair. Why is this possible? From the parents, this child received two genes - the dominant gene of dark hair (which manifested itself) and the recessive gene of blond hair. This recessive gene can interact with the recessive genes of the partner at conception of the child and win in this "fight". Thus, a person can inherit genes even from distant relatives, for example, from some great-great-grandmother, which can become a surprise for parents.
Sometimes the same gene can perform several functions at once. For example, for the eye color there are several genes that are combined in different ways. But some regularity can be traced. For example, black-eyed parents will not have blue-eyed children. But brown-eyed children are born most often with brown-eyed (with various variations of shades) parents, but blue-eyed ones may well be born. At parents with blue or gray eyes, most likely, there will be blue-eyed or gray-eyed children.
It is difficult to predict the growth of the child and the size of the foot. Some predisposition to this or that growth can be traced, but here everything depends not only on genetics. Of course, high parents have a child more than average. But much also depends on how the future mother used to eat during pregnancy, how the baby was fed, what diseases he had, and so on. If the child as a child is well and properly fed, sleeps, moved a lot, went in for sports, then he has all chances to achieve high growth rates. Also, sometimes even facial expressions are genetically transmitted to the children from the parents, facial expressions.
Character traits, temperament, too, are transmitted genetically, but it is very difficult to predict. But the nature of the child is not only genetics, it is also education, environment, position in the society. Children also adopt certain traits when communicating with their parents, so parents should be cautious and vigilant - show good qualities, show children a worthy example of behavior.
And, of course, the level of intelligence, mental abilities, inclination to various sciences, pursuits, hobbies, too, are transmitted genetically (probability - up to 60%), for example, propensity to music, dance, sports, math, drawing and so on. In addition, even taste, aroma and color preferences are inherited, for example, love for hot or sweet and the like.
There is an opinion that boys are more like a mother, and girls are more like a father. This is true, but only partly. And in fact, boys often look very much like their mother, because they inherit from her X-chromosome, which contains a huge number of genes responsible for appearance, and from the pope they get the Y-chromosome. Girls receive the same X chromosome from their father and mother, so they can be similar to both, and to the other parent.
The sex of the unborn child depends entirely on the man. Female sex cells have only X-chromosomes, which means that any ovule during conception, respectively, contains only X-chromosomes. And male sex cells contain both X and Y chromosomes. Y-chromosomes are responsible for the male sex of the child. Thus, if a female X chromosome meets a male X chromosome, a girl will be born. And if a female X chromosome meets a male Y chromosome, then a boy will be born.
In fact, it does not really matter what sex a child will be, and what color it will have eyes and hair. The most important thing is for the child to be healthy and happy, and his parents too! Now you know how important human genetics, parents, what a child will be, depends on your heredity! Do not forget to lead a correct lifestyle!