Rita Arens' post Whose Boobies? on BlogHer caught my interest.
In this and other posts, she is honest about not being entirely successful at breastfeeding her child, because she had difficulty identifying breasts as anything, but sexual. In this post, she mentions misgivings that she and other women have about wet nurses and cross nursing (nursing some one else's child). Some of the concerns that she cites are medical issues, cultural taboos, and intimacy concerns.
While I think these do play a part, to me the most significant factor that has changed is the family structure. In the current age, we think of the nuclear family as a good thing. The basic family unit is now mom, dad, and kids, with little extended family around. We live together, work together, and bond together in these units. A reliance on someone else for bonding or emotional sustenance is a kind of failure, especially for the mom. In the past, and in some places now, a child is raised by an extended family. A baby could be picked up and comforted by anyone. There were many hands-- and many mammaries-- to share the work. Extended families were the social safety net. These arrangements are what is denoted by the phrase "it takes a village to raise a child."
In this analysis, milk banks are a little more acceptable than wet nurses, because only the nourishment is being transferred. Actually, it's illegal in the US to sell breast milk, because trade in bodily fluids, such as blood, is prohibited. Hence, we have blood banks and milk banks. A volunteer blood donation program generally has higher quality blood (e.g. fewer pathogens) than programs where donors are compensated financially for their contributions. (Cue the image of the homeless person with the leaking bandage on his arm and a few dollars in his pocket.) Consequently, one certainly couldn't make a living by selling breast milk. But what about providing wet nursing as a service?
While we're at it, why are men allowed to donate sperm and receive financial compensation? Sounds like a double standard, I say. It's far less medically risky and socially damaging to share breast milk than sperm. There are many children out there who are wondering who is their anonymous sperm donor dad.