newbornsFirst, we have to consider that the early development of newborn and children, depends on too many factors related to the own body of the baby or the kid, and also on external factors.
Having this in mind, the next is to picture how those internal and external factors influent the growth of the children.
If we talk about the internal ones, we could mention those inherent to the child's genetics and physiology, like the healthy or the good DNA non-causing diseases that could affect the normal growth of the baby, for example.
And, if we talk about ones regarding external factors, such as the influence of a bad environment, like a contaminated one, or the influence of pollutants presents on the air, on the water, or in the food, like some toxic gases, or heavy metals, that, somehow, inhibit or affects in a negative way the normal growth of the children in a neurological scale, for example.