We were designed by God for adaptation. This means we are designed to change based on experience. This change is not mere change in beliefs, but actual physical change, including change in neural wiring and genetic expression.
We all recognize that if you decide to start working out at the gym that over time you will build muscle, improve oxygen utilization, burn fat, change the metabolic rate of your body, improve blood flow, build new capillaries throughout your brain and body, etc. All of this remodeling happening in the body requires a change in gene expression. Genes will be turned on and others turned off to accommodate these changes, which are occurring based on choices you are making.
This type of gene expression change occurs throughout life. Identical twins at age 5 have 95% of their genes expressed the same, but by the age of 70 less than 5% of their genes are expressed the same. Life experience alters our gene expression and we do pass along not just our genes, but the instructions on how our genes are to be expressed to our children.
Further, the foods we eat change how our genes are expressed and such expression can be passed down to our children. Genetically identical mice randomized into two groups and given the exact same diet were then to have pups that were genetically identical. But during gestation one group of these genetically identical animals were given the addition of B12 and folate in their diet. The pups born to the mothers with the nutritional supplements had different color fur than the genetically identical pups born to the mothers without the nutrients. What this means is that the diet of the mother changed the expression of genes in their pups. And this fur color change (gene expression change) was passed down 3-4 generations even though the pups’ diet contained no further B12 or folate. (New Scientist August, 2003, Novemeber 13, 2006).
Thus when we read in the Commandment that God punishes the iniquity of the father’s to the third and fourth generation of those that hate Him, we realize God is informing us of His design and how He created us for adaptation, with the ability to change ourselves and pass such changes along to our children. If we live lives of healthy living and gain victories over temptation, then we pass along those advantages to our children, but if we live indulgent lives, then we pass along genetic expression disadvantages.
However, recognize this, that our inherited genetics do not determine destiny. We are all free moral agents and we all have the ability to make choices, which will change us for either good or ill. This means regardless of our starting point it is our life experience, our choices, our beliefs, our experience with God or rejection of Him which ultimately determines the final outcome of our lives. As we pursue God and grow in His love we will experience change, change of mind, rewiring of brain, and genetic expression change such that every cultivated and inherited tendency to evil will be overcome. What an incredible God we serve!