Some excellent points made above.
I think we can all agree(?) that in some cases, there could appear to be positive material outcomes from surrogacy for the child (leaving aside for a moment all the issues for the birth mother - I would also be very interested to hear of any examples of how women being prevented from choosing to be surrogates has any negatives for them. But I digress).
However....
One or two cases of happy surrogate children, anecdata, can not be extrapolated to society as a whole. We don't know how unusual this positive outcome is, but all available evidence suggests it is very unusual.
As others have said, there is plenty of evidence that attachment issues result from babies being removed from their mothers soon after birth. These can manifest in later life and colour all that person's subsequent relationships. These can't be erased by other material benefits that the child may gain.
So, there is no point arguing about whether or not the children will suffer mental health issues - evidence shows they as a group do (granted, there may be the odd exception, but that's not what were talking about). It is arguably impossible to weigh up how much the potential material advantages of being raised in a wealthy /loving home , neither of which are guaranteed, make up for the probable mental health disadvantage of being a commissioned baby. The question therefore is:
'knowing that there is evidence of probable mental health issues, attachment disorders, genealogical bewilderment etc, to what extent is this acceptable to knowingly inflict on a child in order to satisfy the commissioning parents desire for a baby'.
I think some here, myself included would argue that it is never acceptable.
For those who believe that it is acceptable, how do we as a society then decide how much damage is acceptable? How do we measure it? How do we implement safeguards to prevent this line from being crossed? When forming policy, we need to understand how this could work for society as a whole, not just some specific situations in which it was, luckily, apparently ok (that's a bit like saying 'there's no need to wear a crash helmet, I don't bother and I've been ok'- a sample of one is not statistically significant). If you say you agree with surrogacy but don't explain how it could / should work safely for all, you can't expect others to take your argument seriously.
If we can agree that there is likely some psychological harm to the child, surely we can agree that this, then, is a problem that society should be concerned with (rather than shrugging our shoulders and saying 'women's right to choose innit').
If you would argue that there is no evidence of harm, I would invite you to look at some of the links posted upthread before forming a response.