I think the research speaks for itself and the links have been provided.
I haven't slept in 4 months, I wake around 6/7/8 times a night with my 6 month old. No way would I let her cry herself to sleep because I can't be bothered getting up. Flame me all you like but I didn't have a child so I could leave them alone to cry. At 6 months a baby has spent more time inside their mother than in the world that is why CC is damaging to an infants mental health. I don't know why people even have to question whether it's ok or damaging? You are talking about an infant, who is only just discovering they are a separate being.