I have stumbled upon a disturbing phenomena, whereupon a starving and dehydrated baby left in a sparring pool immediately returns to good health once bonded with the mother.
This leads to a hypothesis where we use noodle theory and the extended baby shield theory to conclude that babies share almost a second circulatory system with the mother, intertwined through the 'tangled' teeth or the beard, living off the nutritious alcohol pumped from the mother.
If this is true, then it also has heavy implications that the Dwarf baby is actually formed when a female spore is fertilized, and grows to be a polyp, where it simply falls off once it has grown into sufficient mass, where it has to be carried by the mother from thenceforth. This is heavily suggested as to why Dwarf babies always fall one tile from the tree, so to say.
This would ultimately support spore theory, and would explain why mothers feel tragedy from losing their child, despite happily using them to protect their own bodies - they are saddened by the loss, as one would be to lose a limb, yet would not hesitate to save their own separate body if it were at the cost of their baby.
And it would also explain why babies are almost entirely emotionless.
They share the emotions of their mothers. If the link is severed by the mother being killed, this causes intense distress amongst the baby, resulting in the sudden surge of emotion and unhappiness.
Once the baby grows to childhood, the link is broken, but the memory of it still remains, engraved in the beard, also explaining the hive mind in the average dwarf fortress. When they are happy to have talked to a friend recently, they are really talking about the quantum entanglement of the beard/teeth.
I urge Overseers to closely follow the lives of babies in their fortress, and alert your nearest Chief Medical Dwarf to unusual phenomena observed.
Babies suddenly bursting into flames for days on end, forging anvils from cat bone and slaughtering everyone in sight are still classed as unusual occurrences.