A forest fire begins when two pieces of wood rub against one another, being agitated by the wind. Actually, however, fire belongs neither to the wood nor to the wind; it is always different from both. Similarly, the life force of the living entity–the soul–is different from the ovum and semen of the human being. Although the conditioned soul has nothing to do with the reproductive cells of man and woman, he is placed into the proper situation because of his work (karmana daiva-netrena). Life is not, however, a product of two secretions, but is independent of all material elements. As fully described in Bhagavad-gita, the living entity is not subject to any material reactions. He can neither be burnt by fire, cut by sharp weapons, moistened by water, nor dried by the air. He is completely different from the physical elements, but by a superior arrangement he is put into these material elements. He is always aloof from material contact (asango hy ayam purusah) but because he is placed in a material condition, he suffers the reactions of the material modes of nature.
Source: A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Srimad Bhagavatam”, Eighth Canto, Chapter 17 – Text 23