Where do we draw the line on that? Paid kidney donation? Or living cornea donations? We know that pregnancy and birth take a major toll on the mother, almost without exception. There's plenty of evidence that almost all surrogates are already mothers, with other children who are at risk if they lose a parent.
What about a parent who does a dangerous job and takes money (wages) for doing it. Do you think it is OK for their children? I mean anyone from a firefighter to racing car driver is taking a risk. My husband was a police officer, he was permanently disabled in the line of duty when I was pregnant, it has had a big impact on our children, he could never carry them round, never have a game of football with them. I because his carer as well bringing up 4 kids.
It is hard to know where to draw the line isn't it. Particularly hard with DH who was a rank who could have been happily sat at his desk but decided to be out there with his unit.