What is the difference between identical and fraternal twins?

Answer by  traumatised (3285)

Identical twins come from one fertilised egg that splits; they are identical in every way down to their dna. Fraternal twins come from two separately fertilised eggs. Although they share a womb, they are only as alike as any siblings. Identical twins are always same-sex; fraternals can be different.

Answer by  Diddum (348)

identical twins have the same DNA because they derive from a single maternal egg which at an early stage of duplication become two separate but identical individuals. Fraternal twins are just like brothers, since they come from 2 different eggs, so they can be very different, say male and female.

Answer by  GinaD (400)

Identical twins come from one fertilized egg that splits into two, very early in its development, when it is just a few cells large; each half continues to develop and form a baby with the exact same genetic material. Fraternal twins occur when the mother releases two eggs and both are fertilized. These children have different genetic material.

Answer by  Helenaneesh (68)

In identical twins, only one ovum is impregnated by only one sperm. Then the egg divides into two embryos. These eggs would have the same chromosomes which look alike even the sex. In non identical twins, the ovum is impregnated by two sperms. They have different chromosomes and they dont look alike.

Answer by  Anonymous

There is a third type of twinning: polar body fraternal which happens when an egg divides into two identical eggs prior to fertilization... maternal dna is identical, paternal is not, as two separate sperm fertilized the two identical eggs. Basically, half-identical.

Answer by  shari (52)

Identical twins come from the same fertilized egg in the womb, generally they are the same sex and look alike. Fraternal twins come from two seperate fertilized eggs in the womb at the same time, the children may or may not be the same sex, or look alike.