If you see him in person, he really is the cutest little peanut and proportionate & all. He just runs small! We all come in many shapes and sizes.
I decided to go back in my other boys' baby books and check their head sizes. Wow! Gray's head right now at 9 months old is 16.8 inches. Carter's head AT BIRTH was 15 inches. Don't forget, Carter has always been big (born 9 lbs 12 oz and Gray was just 7 lbs 5 oz at birth.) And Noah, born 7 lbs 7 oz, and even though he is my oldest, is growing normally and right there in the middle. I think they are all three just perfect the way they are.