In the Vedas, long before people knew about gods such as Shiva, Vishnu and Brahma, there was a story of how the god of heaven committed incest with the goddess of dawn, his daughter. Now this is called the problem of primal incest, which is found in almost every mythology.

The problem is this: if in the beginning, there was 'the one' and then then he or she created 'the second', the relationship of the second with the first can be of either sibling or of child. Either way, a sexual relationship between them is incestuous, which is taboo in most communities around the world. For example, according to biblical lore, Eve was created from the rib of Adam, so technically, that makes her the daughter of Adam. In some versions, they are siblings born like two parts of a single fruit. Therefore, again, the relationship between them can be argued as incestuous. Stories such as these must be taken in a metaphorical spirit, as metaphors of a primal time, rather than something literal, indicative of some primitive tribal practice.