If a man does a great injustice to another in his life, then, after his death, his son will be despised for having had such a father and in some cases the injury might be so serious that the effect would reach to the grandson, etc., or a man may, by wrong living, fall into consumption and give that disease to his children unto the third or fourth generation. “Both physically and mentally the sins of the fathers may be visited upon the children.”
(‘Abdu’l-Bahá: Daily Lessons Received at ‘Akká 1979 ed., pp. 45-46)
Whether your illness is the result of any inherent constitutional weakness and inherited predisposition in a question which you should refer to experts in the medical field, though even expert physicians themselves may in very few cases find it exceedingly hard if not altogether impossible, to give a final and decisive answer.
(Shoghi Effendi, Lights of Guidance, p. 377)