Nobody will begin to argue with that between boys and girls there is a difference. One only external distinction of that costs? But than also why they differ from each other? 
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1. It appears, representatives of the weaker sex hear and relatives to high-frequency distinguish sounds much better than representatives of the strong. It explains that fact that mother in the sleep will hear crying of the child, and the father will quietly sleep farther. But, in turn, the man will understand quicker, from where the sound goes. Such ability helps the hunter to define a site of future production.
2. Still girls have wider peripheral sight. They are capable to see distinctly space at an angle in 45 degrees up, down, to the right and to the left. The nature made it not simply so, after all with such ability it is much simpler to any female to watch that cubs did not run up and to them threatened nothing. But boys possess ability better to see forward, afar, that too helped with the ancient world to them on hunting.
3. Speech at them too differs. At girls for it areas both in left, and in the right hemisphere of a brain, and at boys only in one of them answer. Still small men use only three tones while small women actively use five in speech. For these reasons of the girl are more talkative that helps females to distract, entertain and calm kids, and young people are more silent that once again helps them on hunting.
4. At the age from 2 till 3 years children meaningly start to feel the belonging to this or that floor. They acquire role behavior, following an example parents.
Therefore boys begin, as the father, to potter with machines and something to repair, and girls as mother, to prepare and play dolls that speaks also a maternal instinct. Laziness to read? Then listen!
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5. Because of distinctions in mentality, representatives of the stronger and weaker sex too get on well at school differently. From first school days of the girl study better as they better developed speech, and boys, feeling on their background is sillier, become more shumlivy and restless. But subsequently many girls start to lag behind in those subjects in which the spatial imagination is necessary, and boys on them, on the contrary, receive more decent estimates. Many parents, without knowing such subtleties, abuse the children, holding up as an example the brother or the sister that by no means it is impossible to do.
Now we know that boys and girls differ not only outwardly, but also internally. Perhaps not for nothing there is an opinion, what women – from Venus, and the man – from Mars?.]