People are apt to say of a gifted man that he must be the offspring of a gifted family, that he must have inherited his talents from his forefathers. When we observe the physical processes from the occult standpoint we know that it is not like this. We can, however, in a certain sense speak of processes of physical heredity, and we will take an example.
Within a period of 250 years, twenty-nine musicians were born in the Bach family, among them the great Bach. A good musician needs not only the inner musical faculty but also a well-formed physical ear, a special form of ear. Laymen cannot perceive the differences here; it is necessary to look very deeply, with occult powers. Although the differences are very slight, a particular inner form of the organ of hearing is necessary if a man is to become a musician, and these forms are transmitted by heredity they resemble those which have been present in the father, grandfather and so on.
Suppose that on the astral plane there is an individual who acquired great musical faculties hundreds or thousands of years ago; he is ready for reincarnation and is seeking a physical body. If he cannot find a physical body possessing suitable ears, he cannot be a musician. He must look around for a family which will provide the musical ear; without it his musical talents could not manifest, for the greatest virtuoso can do nothing unless he has an instrument.
Source: Rudolf Steiner – GA 99 – Theosophy of the Rosicrucian: VII: The Technique of Karma – Munich, 31st May, 1907
Translated by M. Cotterell & D.S. Osmond
The great Rudolf Steiner Quotes Site 