Im thinking if they put all those research materials and the power of magic, they will concluded that they can induce artificial insemination of sperm, or like the modern technology of producing a child between egg and sp**m cells.
If both of them are not able to produce enough egg or sp**m cells count, they can count on science like they do now...
The level of technology shown to us by them until now was enough to study how life was being produce inside the womb or how it happens.
Well, to be frank, im glad this is kind of a plot.... to think that our special MC has a chance to be the one who will produce such an excellent child to the queen, not Mirakaba...