The abuse of other human beings is taught to children by parents and community, mainly through religious indoctrination. Contrary to the supernatural idea that human beings are born evil, evil human beings are created by bad parents.
Children are a work in progress
Human babies arrive with a big head because prenatal growth concentrates on the brain, which is housed in a pudgy body of little use. After its arrival, the infant body's chemical factory will rage day and night to build a child who will learn how to chew solid food and control its bladder and anus; it will be expected to respond to directions appropriate to its age and to learn to stay within the safety lanes laid out in its environment. Similar mammalian parent-child interaction is accomplished by the raccoon, bear, or giraffe in less time, but these creatures are more mature at birth and have less to learn. Birds can be extremely dedicated parents. Ideally the child's physical needs will be met, and it will be loved. Parental love is an instinct in humans, but in our species the process can go radically wrong.
For early humans, a malformed baby was a monstrous thing; nature provided the designs for all its creatures, and it was the duty of the parents to face the fact that there was no future for a physically deficient human child. The environments that early humans endured were not composed solely of physical challenges, but eventually included the mind: choices had to be made. Parents could return the defective infant to the great mystery from which all plants and animals arose, or indulge the emotional attachments that grow between us.
Research is revealing the hundreds of genetic mistakes affect the functions of the human body, some serious, some not so. How could such imperfections not occur? The trillions of steps that must be repeated to grow a single human will not be occur perfectly, ever. Individuals with physical problems that would have meant death in earlier times may flourish today with intervention and care. The brain is a special case; problems in development can result in little normal function, but as a society, we value the life of the child and will do our best to encourage its survival. Our ancestors would have judged this leniency to be against nature and wildly out of order with proper behavior. Attention to physical perfection was important; we can observe this in offerings to the gods, which had to be pure and unblemished, whether or not the gift was an animal or a plant.
Parenthood for our ancestors was not as it is today; we approach having children as if it is an experiment, which is played out against a history of radical ideas about what it means to be human. Early people believed that their ancestors had not only solved the big questions, but had passed on rules to cover every detail of life. The good life was a matter of preserving these instructions for the next generation by means of prescribed rituals that must be performed correctly, and on schedule. The idea was to stick to the rules, a strategy that served humans well for thousands upon thousands of years.
What about those infants that were returned to nature by natural causes or by parental choice? Many could not have survived, even with modern technology. Others were an insupportable drain on any group dealing with chronic starvation. Despite physical defects, a few surely had the potential to develop inventive minds, and would have been sources of innovation that benefited the group, but the investment needed to raise a child to adulthood prohibited such a gamble. Many myths describe handicapped individuals whose talents were highly valuable to society; the lame blacksmith Hephaestus, and the blind poet Homer are examples.
How much talent continues to be wasted because certain Americans don’t like the package it comes in? The selective rejection of people labeled as inferior impoverishes a culture. A society that can get past prejudice by broadening the scope of accepted thought and behavior reaps the rewards of contributions made by those who formerly were passed over or persecuted. The United States has come far in this regard, and we have grown rich and powerful as a result. Why then do we fight success with renewed stress on petty distinctions based on ancient prejudice?