At just 5 1/2 weeks, a developing fetus can sense touch to the lips and nose, and by 12 weeks almost the entire body is responsive to touch. These are just some of the facts detailed in Dr. Lise Eliot's book What's Going on in There? How the Brain and Mind Develop in the First Five Years of Life. Dr. Eliot talks with Dr. Oz about the development of a fetus during pregnancy and shares insight into when a fetus develops the senses of smell, taste, sight and sound.