Children, in a state of innocence, would have possessed the power of motion suitable to their age; for in natural things we ought to follow the teaching of Nature and in supernatural things the authority of Scripture.
Human infants are endowed with more brain than the young of other animals; hence, owing to the greater amount of moisture, their nerves of motion possess less power for the movement of their members; but in a state of innocence they would have had sufficient for the actions of childhood without any defect. And since nothing would have been wanting for the perfect fulfilment of all the requirements of Nature there would also have been a distinction between the sexes; for, as diverse grades are required for the perfection of the universe, so the variety of men and women is required for the perfection of human society.
- text taken from Compendium of the Summa Theologica of Saint Thomas Aquinas, by Bishop Berardus Bongiovanni