Is it in the genes or in culture?

"we receive each chromosome intact from one of our two parents" (the selfish gene page 25)

We as humans go trough a process before we are even born we are divided as egg and sperm this means that we are formed by two half’s each one with 23 chromosomes.
This means that we are all begun by the mixing of the genes from our parents, the novel suggests that when this happens the gene pool gives us the selfish part that is passed on by our parents.

If I must say all this scientific explanation about being something inside of us which we cant avoid is a lie. All humans have reasoning what about the ancient times when the recourses were gathered and distributed equally to everyone. It is actually a society problem and the fact that wile time goes by we all become more materialistic.