Noah left the impression of being misshapen, his head or his body or his legs or his mind; but no misshapen member could be recalled. Pa thought he knew why Noah was strange, but Pa was ashamed, and never told. For on the night when Noah was born, Pa, frightened at the spreading thighs, alone in the house, and horrified at the screaming wretch his wife had become, went mad with apprehension. Using his hands, his strong fingers for forceps, he had pulled and twisted the baby. The midwife, arriving late, had found the baby’s head pulled out of shape, its neck stretched, its body warped; and she had pushed the head back and molded the body with her hands. But Pa always remembered, and was ashamed.
– John Steinbeck
The Grapes of Wrath, Chapter 8. Noah is described as being strange. This passage suggests that some disfigurement happened when Pa Joad had to use his strong hands and fingers for forceps at Noah’s birth. Because of this Pa feels shame.