In the case of identical twins, the fertilized egg uses just one sperm for the process of fertilization. After that process is complete, the egg will then split into two different parts and create two different embryos. As a result, the babies that are born identical will share the same genetic characteristics and also share similar physical characteristics too. However, in the case of non-identical twins, the female body releases two different eggs which are then fertilized by two different sperm cells. Hence, the creation of fraternal twins means that the babies will not share the same chromosomes and hence will not have the same genetic or physical characteristics.