Although twins born are occurring in all societies, its study continues to fascinate just because, we are not sure about the reasons for its occurrence. Therefore, right understanding of its typology, factors responsible for twinning, monozygotic and dizygotic multiples, occurrence and their distribution become prime requisite for the study. Early studies and statistics available direct us towards genetics and environment’s role in the existence of above phenomenon. So, where does the answer lies, is it in either of them or is it their combination responsible, which is the need of hour in study of human variation.