Not everything. Women who are violently raped and get pregnant and have the baby have perfectly normal babies. Adopted kids learn great morals from good adoptive parents.
If genes were everything, we should not let children of criminals free. G-d gives every single person a chance to be good. The sins of the fathers...
Precious free will. It’s a gift every person is given.
There is some evidence that violent events affect the sperm and egg and therefore the children.
http://www.time.com/time/health/article/0,8599,1951968,00.html