Twins of different sexes are smarter than their peers

The twins of different sexes may be more socially successful than their classmates and peers. This was proven by several researches held by Universities. According to these researches twins of different sexes are more developed than twins of the same sex and than ordinary children.
Traditionally people consider that twins' development of talking and other skills are not so good as the skill's development of other children. Partially this opinion is connected with the little weight and small height of twins when they are born. And their delay in the development of the talking skills often appears because of the preference to communicate with each other than with other people.
However, the investigations in which four thousands twin pairs took part and 22 thousand their classmates didn't find any differences among children. And the twins of different sexes gave the better points in compare with other kids.
People noticed long time ago that girls are less active at their early age than boys. And boys have some problems in their social and emotional development.
One of psychologists supposed that boys in the pair of twins of different sexes get the skills of talking faster than their peers. Girls also get the benefits from their development communication with boys-twins and becoming more active. The abilities of one of twins are favourable for the development of abilities of another twin.
In general everything depends on parents and individual preferences of twins. If parents are ready to experiment and to educate children, then twins will be the smartest in the world.