This impregnation of material nature is described in Bhagavad-gītā, Fourteenth Chapter, verse 3. Material nature's primal factor is the mahat-tattva, or breeding source of all varieties. This part of material nature, which is called pradhāna as well as Brahman, is impregnated by the Supreme Personality of Godhead and delivers varieties of living entities. Material nature in this connection is called Brahman because it is a perverted reflection of the spiritual nature.
It is described in the Viṣṇu Purāṇa that the living entities belong to the spiritual nature. The potency of the Supreme Lord is spiritual, and the living entities, although they are called marginal potency, are also spiritual. If the living entities were not spiritual, this description of impregnation by the Supreme Lord would not be applicable. The Supreme Lord does not put His semen into that which is not spiritual, but it is stated here that the Supreme Person puts His semen into material nature. This means that the living entities are spiritual by nature. After impregnation, material nature delivers all kinds of living entities, beginning from the greatest living creature, Lord Brahmā, down to the insignificant ant, in all varieties of form. In Bhagavad-gītā (BG 14.4) material nature is clearly mentioned as sarva-yoniṣu. This means that of all varieties of species—demigods, human beings, animals, birds and beasts (whatever is manifested)—material nature is the mother, and the Supreme Personality of Godhead is the seed-giving father. Generally it is experienced that the father gives life to the child but the mother gives its body; although the seed of life is given by the father, the body develops within the womb of the mother. Similarly, the spiritual living entities are impregnated into the womb of material nature, but the body, being supplied by material nature, takes on many different species and forms of life. The theory that the symptoms of life are manifest by the interaction of the twenty-four material elements is not supported here. The living force comes directly from the Supreme Personality of Godhead and is completely spiritual. Therefore, no material scientific advancement can produce life. The living force comes from the spiritual world and has nothing to do with the interaction of the material elements.