I've often heard the claim that women are forgetting, or remembering labour and birth pain as being less severe. Some people say that this mechanism has an evolutionary advantage, as if it didn't exist women would avoid having more babies...
Is this explanation possible? I'm assuming most animals don't know the relation between contraception and labor, so they won't be able to avoid labor even if they wanted...
How long have humans been aware of this relation, and is it possible that evolution has been able to work in that time-span?