Most of my clues didn't come until my son was around 12 mos (or maybe I was just too sleep deprived to notice). By that age, he already had favorite books and authors and was finding Lowly Worm in Richard Scarry books. By 18 months he would sit for 45 minutes or more of reading, prompting a librarian to comment on his long attention span. He also knew the letters and their sounds really early, but I didn't think anything of it until later. I had no clue that he might actually be so bright that it could be a problem until he started sounding out words in the newspaper at breakfast one day when he was 2 1/2. I replaced the newspaper with Hop on Pop and realized to my shock/horror/amazement/excitement/disbelief that he could read much of the book--and he hadn't memorized it. From that day on he read everything--signs, tags, the names of his crayons and the tiny print on the bottom of his Matchbox cars, and I realized I had a special case on my hands. By age 3 his reading was scary enough that I started hanging out here!