twins

Introduction and Kinds of Twins


Twins are multiple babies who are conceived, developed in the womb, and are born at the same time. For centuries twins have intrigued people. Twins are especially important to science for they allow researchers to estimate how genes and environment interact to influence our behavior, physical health, personality and so on.
There are two main types of twins: Fraternal twins who are also referred to as dizygotic twins and Identical twins who are also called monozygotic twins. Fraternal twins occur when the mother releases two eggs and both become fertilized. Fraternal twins develop separately, have different genes, they are really no more than siblings born at the same time. Whereas, Identical twins come from one fertilized egg that splits in two. The separation can occ...