When did humans link sex to birth?
Most of humanity, there was no link between sex and birth. How would you know if no one told you? Even if you saw “resemblance” tribes were so isolated, their sample size of humanity so small, it would be fair to think this is just what people look like. Sex was urge-driven, orgiastic, and likely disconnected from a stomach growth that lasted for 9 months. The idea that babies come out could have been seen as a natural, accepted thing. To know causation through time—to link an invisible cause to a future effect—would require abstract, symbolic thinking. The conscious realization of this changed history, from hunting to the domestication of animals, to surplus and civilization.