When I read about the psychological damage caused to a newborn baby by being cared for by people other than its mother, I find myself wanting to ask how that works for all the babies who have been cared for in a family group setting where mothers often sadly were very ill following childbirth, those who found themselves in hospital nurseries for similar reasons, NICU for months, aristocratic homes where nanny was waiting in the nursery...
It's thought that we developed an evolutionary advantage by spreading care of our young around a female family group and it's hard to believe that babies don't have flexibility and resilience to reflect that. I think they do.
A lot of research into the primal bond is done from the point of view of adopted children but there have been many differences in the lives of those children, the experience in early childhood being only the first of many. I've read the books and still I wonder if the physical separation from their mother at birth is not in and of itself the cause of deep psychic shock but a powerful metaphor that explains perfectly the trauma of knowing at a later stage that they were given up/relinquished. I think this because we're not seeing similar outcomes in comparable situations where mum and baby were separated - for babies in NICU or indeed children born through surrogacy as far as I'm aware.
In my view there are usually processing tasks in any childhood involving issues of identity (eg., why are we a different colour/why can't we afford that/why don't I see dad/why do the police pull us over more often/why do I get teased about my appearance). Surrogacy as a processing task is considerably easier than adoption because you were always planned for and wanted, often look like both parents and many times are able to meet the birth mother who is often happy to explain that they carried you for loving intended parents.
Being an adoptive parent is just a hundred times harder in every way and it's a hundred times harder for the child too. There's no comparison.