Heredity

The variety of inherited qualities comes from strength and weakness of constitution -- that is to say, when the two parents are weak, the children will be weak; if they are strong, the children will be robust. In the same way, purity of blood has a great effect; for the pure germ is like the superior stock which exists in plants and animals.

‘Abdu’l-Bahá, Some Answered Questions, p. 213

The variety of inherited qualities comes from strength and weakness of constitution; that is to say, when the two parents are weak, the children will be weak; if they are strong, the children will be robust. In the same way, purity of blood has a great effect; for the pure germ is like the superior stock which exists in plants and animals. For example, you see that children born from a weak and feeble father and mother will naturally have a feeble constitution and weak nerves; they will be afflicted, and will have neither patience, nor endurance, nor resolution, nor perseverance, and will be hasty; for the children inherit the weakness and debility of their parents.

‘Abdu’l-Bahá, Bahá’í World Faith, p. 319

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. Whether deficiencies are inborn or are acquired, our purpose in this life is to overcome them and to train ourselves in accordance with the pattern that is revealed to us in the divine Teachings.

The Universal House of Justice, 1995 Sept 11, Homosexuality