When a person becomes materially engrossed, he has no capacity to hear about spiritual existence. Forgetfulness of spiritual existence entangles a man more and more in material existence. Such is the result of sinful life. Various bodies are developed with the material ingredients because of different types of sinful activities. King Puranjana assumed the body of a woman, Vaidarbhi, as a result of his sinful activities. Bhagavad-gita clearly says (striyo vaisyas tatha sudrah) that such a body is lowborn. If one takes shelter of the Supreme Personality of Godhead, however, he can be elevated to the highest perfection, even though he be lowborn. One acquires lower births when ones spiritual intelligence is reduced.