We went through 3 normal (thank God) pregnancies, labors, and deliveries in the 1980’s, and IIRC, we were told that if it DID turn out that the baby had what are euphemistically termed “problems”, that as the parents we were entitled to authorize what was called a DNR, for “Do Not Resuscitate”. This meant, in medical terms, that all possible ORDINARY measures would be taken to keep the baby alive, such as intravenous feeding, but not EXTRAORDINARY, i.e. total life support for an infant in a vegetative state, or with a terrible physical deformity that would not be surviveable under ordinary conditions. The “do not resuscitate”, we were told, meant that basically if the baby wasn’t breathing, they would not put it on total life support.
Now, we did hear stories of parents who SAID that their baby was born with “problems” but that the medical personnel who were present didn’t ask them what they wanted, but simply rushed the baby away into surgery or the Neonatal Unit. We had to take those stories with a grain of salt–so much depends on the hospital involved, for one thing. If you’re having your baby in a big teaching or research hospital, the doctors are much more likely to want to try to keep the baby alive as long as possible. It’s not exactly the same thing as “having new material to experiment on,” is it? Does that sound awfully cynical?
If you’re having your baby at a smaller, local hospital, however, one that might not even have a Neonatal Unit (meaning the baby would have to be helicoptered somewhere else), then I think the staff are much more likely to encourage you, or at least to allow you, to authorize a DNR order.
Also, a smaller hospital will have more time to deal with you on an individual basis.
To address the OP, then, it’s the parents who have the final say. Of course, sometimes a doctor or the labor room nurse will exert pressure to have the decision go the way they want. Most medical personnel are very dedicated to saving life at any cost.
Usually you know well ahead of time that your baby might have “problems”, what with increasingly sophisticated ultrasound imaging techniques. When we first started, all ultrasound would give you was just a basic sort of “baby shape”, but nowadays you can tell all kinds of stuff, including possible birth defects.
So you have time to think about how you want to handle it.
AFAIK, it is never “homicide” for the legal guardians to authorize “pulling the plug”. It IS homicide when someone sneaks into the Intensive Care Unit and pulls your plug so you can’t testify against him, but preemies don’t usually have to worry about this. 