AD of children

There are people who are anxious about having children and there are people who say that they don't want to have children. Though, those are temporary talks and sooner or later they all get married and start having kids. At first there is only one kid in the family but it is common that people want to have one more. Psychologists say that it is wrong to have only one child.
A kid who is the only children in the family will be a selfish person, so it is right to have at least two babies. The second baby will distract parent's attention from their first kid and so the first child will realize that except him or her there are other people and one has to care about those people but not only about his or her precious self. It is the best way to explain child the very truth of this life.
Though, it is important for kids to be almost of the same age. The bigger age disparity of children is the harder it will be for them to find mutual understanding. Kids have to play together and to grow up together in order them to become real friends and care about each other. In case if age difference between children is huge they will never be as close as their parents want them to be.
In case if the first child is a girl the age difference of children may be for about six years. Girls have the instinct provided for them inborn and that instinct will make them careful and attentive towards their younger brother or sister. But there is no way for them behavior of a boy, they are of different nature and it is more likely that children will never be close to each other.