This is clearly a highly emotive subject and there are strong views on all sides. It seems to me that several points are being conflated and that it would be helpful to consider each separately.
Firstly, the rights of the surrogate. Can a woman consent to carrying and birthing another couple’s/person’s child, given the risks that this brings? Pregnancy always brings some risks for the mother - risks of complications, pain, even death. We accept that a woman can accept these risks in her own pregnancy. Can a woman enter into this for others? For me the answer is yes - but only if appropriate safeguards are in place. This includes medical screening (both physical and mental health), mandatory legal advice and counselling independent of the intended parents (these are all proposed in the Law Commission paper). If fully informed of all possible outcomes and risks, and sufficiently healthy to undertake a pregnancy, I believe it is the right of the surrogate to make an informed decision as to what she wishes to do with her own body. A further question about surrogate rights is can a woman consent to the legal parentage of a child she births being vested in the intended parents from the moment of birth? Again, for me the answer is yes, providing the safeguards outlined above are followed, and providing there is a further safeguard in the case of a change of heart (which is also in the Law Commission paper, and which I understand to be extremely rare in altruistic surrogacy cases despite hearsay to the contrary).
Secondly, the impact on the child. This is worth splitting into two - the immediate post birth trauma and the longer term outcomes. Firstly, in relation to birth, this is always somewhat traumatic to the child - leaving the warmth and consistency of the womb and entering the world and all its many variations. If the baby is welcomed into the arms of its intended parents, who then go on to love feed and care for their much-wanted baby, this is surely what we mean by giving the baby the best start in life. Granted, the baby recognises the surrogate’s voice. But within a few days it will grow to bond with its IPs (if not before - I am 7 months pregnant as a gestational surrogate and this baby hears its IP’s voices every day). Many conventional births unfortunately do not lead to immediate love and bonding from their biological parents - yet we do not advocate screening parents before allowing people to procreate. Is this really a compelling argument against bringing a much loved and wanted child into the world? I don’t personally believe so. In relation to longer term surrogate child outcomes, this is difficult to assess due to small numbers and sample sizes, and the differing demographics of IPs from the general population. However if the IPs are open with the child about its origins from birth - as my IPs will be with this child and as is common in altruistic surrogacy - what disadvantage would the child born through surrogacy have? He or she knows from their earliest days how much they were loved and wanted and that their surrogate was a part of their amazing journey into the world.
Thirdly, the rights of the IPs. The many evocative examples given on this thread about IP rights to make decisions during a pregnancy are grounded in commercial surrogacy as seen in the US. In the UK the IPs have no rights to decide what the surrogate does in respect to such matters as diet/exercise, screening, termination etc. This is entirely the surrogate’s arena and is why it is so important that there is a good mutual understanding, trust and alignment of views before undertaking any surrogacy journey. This should be covered through counselling and in the surrogacy agreement as suggested by the Law Commission. As with any pregnancy, but more so with surrogacy, there will be a large number of interested parties (including other relatives and friends) who may have strong and conflicting views on important matters. Even in a conventional pregnancy you may see different views between the mother and father in some areas. At least in a surrogacy arrangement these are likely to have been discussed and considered up front - unlike a conventional pregnancy. I’m not saying any of this is easy - but neither do I believe it to be insurmountable with the right support and thought upfront and throughout.
Finally and most contentiously, the issue of commercialisation and payment. All my comments above are framed in the context of altruistic surrogacy as it currently exists in the UK. A move to commercial surrogacy would be a sea change and introduce a host of other different and difficult arguments. However to my mind it is worth clearly separating this from the points above and debating the merits and issues of commercial surrogacy separately.
I recognise there will never be full consensus on all points but I personally find the strong emotive language being used by some on this thread blurs some of the issues above.