These things go even farther. There are human beings (and so there were in former epochs of the earth) who never look up to the stars their whole life long, who do not know where Leo is, or Aries or Taurus; they have no interest in anything in this connection. Such people are born, in a next life on earth, with a body that is somehow limp and flabby. Or if, by the vigour of their parents, they get a model that carries them over this, they become limp, lacking in energy and vigour, through the body which they then build for themselves.
And so it is with the entire constitution which a man bears with him in a given life on earth. In every detail we might refer it to the interests he had in the visible world — in an all-embracing sense — in his preceding life on earth.
People, for instance, who in our time take absolutely no interest in music — people to whom music is a matter of indifference — will certainly be born again in a next life on earth either with asthmatic trouble, or with some disease of the lung. At any rate, they will be born with a tendency to asthma or lung disease. And so it is in all respects; the quality of soul which develops in our earthly life through the interest we take in the visible world, comes to expression in our next life in the general tone of our bodilyhealth or illness.
Source: Rudolf Steiner – GA 235 – Karmic Relationships, Volume I: Lecture V – March 1, 1924