Our appetites and inclinations are strongly influenced by the condition of our physical makeup, and our bodies are in varying degrees of health, depending upon factors such as heredity, environment, nourishment and our own treatment of them. Genetic variations occur, producing conditions which can create problems for the individual. Some conditions are of an emotional or psychological nature, producing such imbalances as quickness to anger, recklessness, timorousness, and so forth; others involve purely physical characteristics, resulting not only in unusual capacities but also in handicaps or diseases of various kinds.