Mahendra kumar* & H.N.Tiwari
Dept. of zoology Ranchi University, Ranchi.
Received 6th July 2007; Revised 17th August 2007
Abstract: Twins are the product of Genetic as well as non-genetic influence that result into the Monozygotic, Dizygotic and siamese twins. Out of these three the frequency (in percentage) of occurrence is more in case of Monozygotic twins. Where as the percentage of occurrence of Siamese twins are rare.