How Did Humans Figure Out That Sex Makes Babies? Slate

[Viva_La_Revolution]

When the Explainer asked you to vote on a favorite unanswered question of 2012, the majority opted for a rather lascivious query regarding why rich ladies sunbathe topless, and the Explainer has duly delivered your pound of flesh. But in perusing the runners-up, another question so intrigued the Explainer that he could not resist answering it as well: When and how did humankind figure out that sex is what causes babies? It’s not exactly the most obvious correlation: Sex doesn’t always lead to babies, and there’s a long lead time between the act and the consequences—weeks before there are even symptoms, usually. So roughly where do we think we were as a species when it clicked?

Basically, since the beginning. While anthropologists and evolutionary biologists can’t be precise, all available evidence suggests that humans have understood that there is some relationship between copulation and childbirth since Homo sapiens first exhibited greater cognitive development, sometime between the emergence of our species 200,000 years ago and the elaboration of human culture probably about 50,000 years ago. Material evidence for this knowledge is thin, but one plaque from the Çatalhöyük archaeological site seems to demonstrate a Neolithic understanding, with two figures embracing on one side and a mother and child depicted on the other. A firmer conclusion can be drawn from the fact that, though explanations for conception vary wildly across contemporary cultural groups, everyone acknowledges at least a partial link between sex and babies.

As for how humans attained what biological anthropologist Holly Dunsworth calls “reproductive consciousness,” that part is murkier. Most likely, we got the gist from observing animal reproduction cycles and generally noting that women who do not sleep with men do not get pregnant. But that doesn’t mean that early peoples—or for that matter, modern people—thought or think of the process in the utilitarian, sperm-meets-egg way that the scientifically literate do now.

The rest... http://www.slate.com/articles/health_and_science/explainer/2013/01/when_did_humans_realize_sex_makes_babies_evolution_of_reproductive_consciousness.html