I came in late on this discussion, and it seems nicely-rounded already.
But I have a question - when a woman agrees to be a surrogate only because she needs the money, especially as a means to alleviate poverty (case in point, the majority of the 'surrogacy tourism' in India), how does one keep a check on how the said woman lives during the period? I'm talking specifically of nutrition, other medical/physical issues and medications, alcohol, tobacco, etc.? Wouldn't this be of even more concern in the case of a woman living under impoverished circumstances? Funds provided for nutrition and care could easily be spent on more pressing daily needs.

Are there controls for this? What kinds of rights do the biological parents have to 'check' on the surrogate? What kind of accountability exists?
And how practical would actual checking and monitoring be in a case of 'surrogacy tourism', where by definition, the parents and the surrogate would be in different geographical areas?