They knew she would not be able to carry them to full term. They knew the babies risked being born underdeveloped. They knew she had already given birth to six other children, a factor which makes any pregnancy for her, even of just one child, a riskier venture than usual. By nature of making a multiple birth a possibility, they condemned these kids to being born two steps behind everyone else, and for what good reason? I cannot think of one.
They endangered the health of these babies and this mother, just because she wanted them, but the children in this story seem to have had no one looking out for their interests. And for what? Not to ensure that someone who had no children could have one. But to prove to themselves that they could do it, that they could deliver the babies. But what of the rest of these kids' medical life? Did the possibility that these children may yes, survive the labor, but perhaps not survive the dangerous early days, months, and even years ahead? Being a premie doesn't end when you leave a hospital. It has affects on children that last much longer, and they may not catch up to their full-term peers for months after they have left a hospital, in some cases even years. Willingly bringing 6 or 8 premies into the world at the same time is like purposely choosing embryos that have a lesser chance of surviving "just to see" if you can make it. And what if they didn't make it? Would those doctors consider themselves as responsible for their deaths as they are now giving themselves credit for their survival?