Punar=again, and Janm=birth, so Punarjanm means - one who has already taken birth before, if he takes birth again after his death, it is called his Punarjanm. If god himself comes on Prithvi, it is called His Avataar, but when a man or animal who has already taken birth, he comes again on Prithvi, it is called his Punarjanm, or Janmaantar Janm... so goes the Kaarmik cycle. Hindu believe in Punarjanm and that is why their Karm are important for them. There are many cases reported and verified of Punarjanm.

All causal beings enjoy different causal desires through perception. A natural time comes, when the causal body gets melted and the metaphysical Karmic seeds come down to the earth along with precipitation, gets accumulated in fruits, flowers and medicines of the nature. Coincidently, the parents to whom a concerned soul is expected to born as their offspring, consumes that concerns Kaarmik seed enriched with nutrition. As a matter of fact the Kaarmik seeds in subtle form enter the sperm and egg of the parents, which on union form the zygote, the indiscernible corporeal body. With the growth and development of the zygote the birth process followed and the life process is expressed along with the sprouting of the Kaarmik seeds. Thus a person behaves and experiences accordingly and the results of his past deeds (Praarabdh) gets reflected on his Sanskaar (present getup).

This is how the deeds of the past life strongly influence the activities of the present life; we are unable to get rid of it and call it as Bhaagya (luck). What we call scientifically as gene interaction to show differential expression with the same genome either brothers and sisters or even twins of one family; can be well coordinated with the Hindu Kaarmik seed concept, which differs from person to person. Otherwise a straight approach that, a soul seeking rebirth seeks a kind of genetic environment, which matches to its own creed (genotype). Moreover, the soul cannot be identified without the body, shuttles between Manes habitat to human habitat and vice-versa which amounts to the cycle of birth and death in nature.