Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

Let's start looking at women holding babies. First, note that they tend to do it with two hands. We are likely to find very few of them doing it with one hand, that is, if we find any. 

Here is a woman doing it with two hands, and we can see both of her hands and where they are making contact. Her right arm is going underneath the baby's bottom, effectively providing a sling for it to sit on, while her left hand stabilizes. And that's why it takes two hands. One would be enough from the standpoint of supporting the weight, but there is leverage involved; the baby could easily pivot away from you. So, one arm takes the weight, and the other arm stabilizes. Check.