In the aforementioned book, Burrus several times cites Nancy Jay’s ( Throughout Your Generations Forever: Sacrifice, Religion, and Paternity ) arresting observation that “birth by itself can never provide sure evidence” of paternity, yet evidence of paternity provides the “crucial inter-generational link.”  That is: Watching a birth, you can tell who the mother is; the mother is the one from whom the child emerges.  Until very recently, there is no similarly reliable empirical way to test paternity.  Yet, paternity is a cornerstone of law and social custom in many societies.

Which means: Paternity has a natural, biological root ( somebody impregnated the mother, or at least somebody’s sperm did).  But unless someone observed the act of impregnation (which is, to say the least, unusual), paternity has historically been constructive, fictive, assigned.

Which also means: Paternity has historically rested on trust.  That red hair might be a recessive gene, or it might be evidence of a rival.

Which also makes one wonder: How does the use of DNA paternity testing affect masculinity and paternity in law and society?  What happens when paternity no longer relies on trust?