I found this research interesting. Scientists have discovered that newborn rats which receive more maternal care have the expression of their genes altered, making them less stressed and fearful in later life.
So it's not just the genes we are born with which matter. What also counts is how the genes are "tweaked" by our experiences and conditions of life.
The experiment with rats might not hold true for humans. If it does, though, it will help to explain the reluctance of many women to leave the care of their young children to others. Perhaps many women do feel instinctively that mother care has a long-term positive influence on their offspring.
It's long been my belief, drawn from my own observations, that boys who receive a strong dose of mother love have a more secure sense of self-esteem than others. It's not that they don't suffer disappointments or negative emotions, but that there is a level they don't easily fall below.
I don't think that father love works quite the same way with sons. The father represents the wider social order. A bad father can therefore produce a son who rebels not only against him, but against the order of society he represents.