avishai, the phenomenon you are referring to is called 'epigenetics'. the environmental effect on one generation is passed on to next few generations thru the epigenetic memory. e.g. effects of famine in a generation may be felt on next two generations. this has very sound scientific explaination. whereas reincarnation beats all logical thoughts.

sorry for deviating but cudn't resist :D

Life moves pretty fast. If you don't stop and look around once in a while, you could miss it. - Ferris Buller.