My oldest was very obvious. Youngest was much less advanced as a toddler--spoke later and with less complexity, didn't meet other milestones as early (I would say he was 6 months behind her, if not more). We thought he was our "easy," less precocious one. As he's gotten older, the possibility that he going to test higher than DD seems more and more likely.

However, he does not have the classic gifted personality like she does. At times he does get frustrated and is a bit perfectionist, and he can be emotionally sensitive--but on the "gifted personality traits" scale, she is like 9+ and he's a 3. He blends in anywhere.