I think they can tell the difference between the remains of a newborn that was born alive then died/was killed and a stillborn baby. I assumed that this made the difference, they knew both babies were stillborn so accepted the story?
I don't think this makes sense, and not least because they showed skeletal remains of a much older baby, so they weren't being even vaguely realistic about it.
I am not a medic but I deal a bit with reports from the archaeology of neonates versus stillborn babies and AFAIK it's still virtually impossible to tell. If a baby has gone through the birth canal you might see the bones in the skull have been moved, but that wouldn't prove the baby was stillborn. If you had more than skeletal remains, you'd be able to see if the lung tissue had ever inflated (ie., the baby had breathed). But they didn't have that so wouldn't have known.
I know there's actually still sometimes controversy over where exactly the line is between stillbirth and neonatal death. There have been cases where parents argued that a baby was born trying to breathe and might have survived had medics not assumed they were dealing with a stillbirth.
Sorry, off on a tangent, but I thought they dealt with this fairly complex issue in a really clumsy way!