The science of genetics, today, states that the physical, emotional and mental characteristics of a person are inherited from his ancestors, through the DNA that he carries.
Our Sanatana Dharma has known this since ages and kept it in tradition. That is the whole concept of ‘gotra’. Through the ‘gotra’ one’s genealogy is traced back all the way up to the earliest members!
Also, we have known that we inherit the qualities of those ancestors!
For instance, don’t we remark about an angry man that ‘he gets angry as if born in Viswamitra Gotra’ ? !!