Twins

It is characterized by opposite features, such as one twin being right handed and the other being left handed, a mole being on the opposite side of one twin's face. This feature is very common in conjoined twins, some to the extent that the internal organs of one twin are reversed. Scientists believe that mirror twinning is a characteristic of the embryo splitting later than in the case of most identical twins. It is nothing to worry about and is just a glitch in the twinning process- (Beardsley 4).
             Half-identical twins are the second outcome in the twin categories. Half-identical twins are the second outcome in the twins categories. Half identical, or polar body twins can occur if an egg divides into two identical halves and then is fertilized by different sperms. The fetuses have about half of their genes in common, those from their mother. Half-identical twins are less alike than identical twins, but more alike than fraternal twins. Mary-Kate and Ashley Olsen are half-identical twins.
             Conjoined twins are the third outcome in the twin categories- (Beardsley 3). Conjoined twins are the most rare among twin births. This type of twin comes from one fertilized egg and therefore are always identical and the same sex. The fertilized embryo begins to split as in other twin pregnancies, but is not completely carried out. This embryo continues to grow as a partially connected embryo- (Beardsley 3). Some types of conjoined twins are much easier to separate than others. Other rare forms of conjoined twins can lead to complicated and costly procedures that can lead to difficult ethical and moral decisions, especially if the twins share internal organs. Conjoined twins are more commonly refereed to as "Siamese twins."-(Beardsley 2). They are called this because of Chang and Eng, brothers who were connected at birth in Siam in 1811. They were joined at the lower chest by a narrow band of flesh through which their lives were connected.