The Ugly Baby in The Passion of the Christ

Lots of reviewers and others have drawn attention to one scene in The Passion of the Christ featuring Satan carrying an ugly baby with hair on its back. Christianity Today have taken the trouble to ask Mel Gibson about this:

What's Up With the Ugly Baby?
Everyone's asking about the Passion scene where Satan is carrying a hideous infant.
by Mark Moring

. . . . It's evil distorting what's good. What is more tender and beautiful than a mother and a child? So the Devil takes that and distorts it just a little bit. Instead of a normal mother and child you have an androgynous figure holding a 40-year-old 'baby' with hair on his back. It is weird, it is shocking, it's almost too much—just like turning Jesus over to continue scourging him on his chest is shocking and almost too much, which is the exact moment when this appearance of the Devil and the baby takes place."