I'm sure you've heard these trite words before: every child is differenet, all mature at different speeds. It isn't so critical that he crawl or walk on the same schedule as his older siblings, and, frankly, the youngest has all kinds of entertainment without going anywhere -- there are two other very mobile children in the house who can fetch, who move around and cause excitment, etc. What IS important, however, is what he CAN do. While not crawling, are his physical skills increasing ? None of my children walked befoe they were 1 yr old, but they all walk now. . . He will get there . . . just realize that the impetus to move isn't the same when there are others around who will move for you. :-) (My sister's youngest -- of 5 -- didn't talk until well after 3 years old. He'd developed a sign language the rest of the kids totally understood and they did whatever he wanted. Why talk ? And, yes, he's 100% fine and in college now)