TWINS 

*Fraternal (non-indentical ) twins : are formed when two egg cells are fertilized ; ech egg by a different sperm so that two embryos are formed fraternal twins can be of the same or opposite sex and they don´t have to lookat all alike . 


*Identical twins : are formed when one egg after being fertilized by one sperm, divides into two halves. The two halves are genetically identical. Identical twins are usually of the same sex.
*Any parent of identical twins will tell you - there is no such thing as identical . Each twin has his or her own separate personality , and that can make all the difference .




*Conjoined (Siamese) twins : are formed exactly like identical twins, but during the split, the embryo does not separate completely to form two separate babies and the twins develop attached to one another.


by : Ana Pascual