Especially before the industrial revolution, parents had sex while their children were (presumably) sleeping in the same room. When and by whom, then the claim that children witnessing sex or pornography traumatising children has come from?

by cantamer

I realise that the title contains several assumptions that may very well be incorrect, in which case please do correct me. I also am very ill informed in the field of child development, and not making a claim that children witnessing (not experiencing) a sexual act in an early age may or may not be traumatising.