Original Sin and Maturity

Before we relegate the notion of Original Sin to the garbage heap of ideas, perhaps we could try recycling it in terms relevant to our more secular age (or the pockets of our age which are more secular-minded).
I am sometimes annoyed when I hear people insist that children are so pure and innocent. Sometimes they even say that about teenagers - usually when defending them against adults, whether abusers, predators, or agents of the law. This is an idealized view of children, analogous to our rosy view of "the good old days" or to our distorted view of someone who is the object of our infatuation. In this view, we are born pure and good, only to be progressively corrupted by adult-dominated society until we become irredeemably evil, or at best impure and guilty full-fledged adults.
Human beings, even very young ones, are much more complicated than that. The newborn, to the best of our knowledge, is an asocial bundle of needs and appetites. The first priorities are to be fed and to avoid discomfort and pain. Others are first perceived as providers and satisfiers. As a sense of self develops, the infant becomes egocentric, selfish, "loving" those providers and satisfiers as providers and satisfiers. It is only as a sense of empathy to others is developed that we can talk of goodness or purity as qualities of that child. In fact, it is one of the main duties of parents to encourage and nurture the growth of the child's empathetic, loving, sociable qualities, which otherwise might fail to develop enough to overcome the initial total selfishness.
Original sin can be understood as the state of the infant, that completely selfish and unsocial state which must be outgrown if the individual is to function properly even as a child. A big part of maturity is to continue the process, to gain the self-control to check the primal selfish impulses with love, empathy, and respect for others, while balancing both personal and social requirements. To a great extent, the criminal personality is one in which this process seems to have been interrupted and halted at an early stage. Such a person is an adult on the outside, perhaps even a seemingly functionally competent one for the most part, but whose emotional life is strongly affected by some early stage of development which has not been successfully completed. We often note that the behaviour of problematic adults reminds us of that of two-year-olds, or seven-year-olds, or fifteen-year-olds; this is not when we are praising their better qualities, but when we are aware of their worst failings.
There are some charming and life-affirming qualities which we notice in children and wish we could see more often in adults, but it is a mistake to overlook the fact that children are complicated beings on the way from a state of pure selfishness and ignorance to what we hope is a mature state in which empathy, love, knowledge, and competence in dealing with the world will be a large part of their self-identity and their identity as seen by others. From this perspective, maturity has a moral aspect, and immaturity - at least immaturity in the adult - can be regarded as sin.