How they appear?

The appearance of several children simultaneously in one family traditionally provokes nervousness in both family and society that is naturally. It is enough to say that researchers in this sphere are not only doctors but also metaphysicians and sociologists. The behaviour of twins is the model of many scientific and practical investigations as well as conclusions.

Two or three fetuses may appear as the result of division of the settled ovule at the early stages of development of embryo. And it also may be the fertilization of two-three ovules simultaneously. In the first case twins are called enzygotic twins or monozygotic twins or identical twins and such children are as like as peas. In the second case twins are called hetero-ovular twins or fraternal twins and they look like ordinary brother and sister born from the same parents.