That happens with people adopting a baby too though. The birth mother 'willingly' gives the child up, (usually willingly!) but the reasons behind it are often sad and upsetting. The vast majority of women giving up a baby for adoption will generally be doing it because she can't raise the baby herself - for various reasons. And it can be devastating for a mother to hand her child over to be adopted (because she can't care for it/raise it herself.)
Behind every beaming, happy couple adopting a newborn, lies a birth mother with a sad heart, crying herself to sleep, and spending decades longing for that child. I never see or hear of people giving the birth mother a second thought, when a stranger adopts their newborn, and she never sees that baby again. And no-one ever says 'oh but what about that poor baby being taken from her natural birth mother...'
Yes, some women in some countries have been used (as a surrogate) by rich people, to carry a baby, and hand it over for £50K or so, (sometimes, more, sometimes less.) But the surrogate gets pregnant knowing the child is going to another couple, and that she will receive money for doing this.
So, playing devil's advocate. How come surrogacy is the work of the devil according to many Mumsnetters, but adopting a baby is not? It's still resulting in a couple who want a baby (and seemingly can't biologically produce one themselves) getting one from another woman, and that baby being taken from its birth mother.
And 'yeah but at least the baby being adopted is going to a home where it will loved and cared for, when the birth mother is unable to raise it' is not a suitable answer. Why are people so feverishly against surrogacy, but absolutely fine with adoption, when the end result is the same? A mother having her baby taken from her, and the baby being taken from its mother..