Your children's genes reflect only their potential, not their destiny. It is up to you to provide the environment that allows them to develop to their highest potential.
As many conventionally unhappy parents did in the 1950s, my parents stayed together for the sake of the children—they divorced after my youngest brother left home for college. I only wish they had known that modeling their dysfunctional relationship was far more damaging to their children than their separation would have been.
Since the conventional belief about human embryology is that genes control the development of the fetus, the mother's role in her child's gestation is deemed to be not much more than providing nutrition, feeding her child.