Of course in the old days, if Aristotle is anything to go by, the idea of the function of the mother was to supply the stuff, while the father supplies the "form". Mom supplies what it's made of, Dad supplies what it is.
But now that we understand a little more, we get that the mother, even in the normal case contributes SOME of the "what" and of the "how" it is.
In NO case is the mother the source of ALL that her offspring is. My mother, though she supplied virtually all the "stuff" of the newborn me, supplied only half of the genes. Yet we do not say she is the "Mother of HALF of Dawg," or any other such phrase. She is the mother of Dawg, the kynotokos.
As I say in addition to the genetic material there is the "stuff." She bore me and Mary bore Jesus, for 9 months. There is a certain awareness, an aching of the back, the need to have the tootsies rubbed, and so forth, all of which is work for the mother, whether she chooses it or not. And whether parturition is miraculous or less spectacular, still the mother is forever changed. A primapara dam is just different after parturition.
So mothering is more than being a source. it is being a shelter, a sacrificer, a participant (as I say, willingly or not) in the formation of the child.
We get that. We do not make more of motherhood than it is.
Of course there are differences in this motherhood, which our friends seem to want to minimize. Mary was in the most intimate and the longest contact with Him the mere thouch of whose garments healed an intractable haemorrhage, and whose hands healed many. I do not think the burden is on us to show that made no difference to her who first believed.
Please do not put inaccurate notions of motherhood in our minds and in our mouths. They do not fit there. We revere mothers, but we do not think they do more than they do. What they do is quite enough.