Monica Holloway

For Monica Holloway's three-year-old son Wills, playtime, birthday parties, and preschool were torture. But within the first year of her son's diagnosis with autism-the fastest-growing developmental disability in the U.S.-she and her husband found something that would raise her son's confidence, elicit his very first belly laugh, and make other children clamor to play with him: Cowboy, a light blonde, brown-eyed golden retriever. Cowboy joined their...