It is a difficult topic to discuss as we do hear from posters like those on here who believe whole heartedly that they are doing the right thing for their family and cannot see that there might be negative consequences. There are studies that have shown babies show neurological changes and changes to their heart rates when separated from their mothers - even when that separation is baby lying swaddled in a cot beside the mother's bed compared with skin to skin contact. There are studies that show that babies recognise the heart beat of their own mothers, recognise and are soothed by their mother's own smell, have a preference for their own mother's breast milk.
We are reluctant to talk about this because few people have a perfect journey through life and sometimes this discussion causes harm through making people feel guilty about their actions that were done in good faith, but it may do more good than harm if fewer people took actions that are know to be 'sub optimal'.
We have all seen discussions where people say 'I did it and I am fine'.. 'My babies were definitely happier because I did X than they would have been if I were Y.' and seeing discussions about the risks or disadvantages associated with doing Y shut down because this is X shaming or reminding people that it is much worse to be shooting up heroin.
We do not know what impact separation from the biological mother (when the baby is welcomed into a loving family) has on later life, not least because there are not enough people who would want to be involved in the research, but based on the evidence we do have, we can assume there is an impact. Do we have the right to inflict what is sometimes called the 'Primal Wound' on children who have no say in the matter to heal the wound of child loss and childlessness of adults? The argument that children would prefer to be here than not is not a strong one - because we do not know what never having been born, feels like.
There are an uncountable number of factors at play on a daily basis, not least in a lifetime, and identifying the single cause of a single outcome is incredibly difficult if not impossible. However, we do know that there are impacts in the same way we do know that babies benefit from the vaginal flora of a mother and benefit from receiving colostrum even if many people born by cesarean are fine as are many people who were not breastfed.
We shy away from these conversations when faced with real life scenarios,, not because our arguments are not strong enough, or because we do not believe it when faced with 'evidence to the contrary', but out of kindness and not wanting to cause harm to people who cannot undo their actions, changing their opinion will not fix things for them.