We knew from very early on... and so did casual onlookers.

Rather than go into detail, I will just share that lists like the following would have been a great comfort to us at that time... so I post (and re-post) the list with hope that it may be of some assurance to others.

A roundup of common Behavior characteristics and early milestones which may indicate giftedness:
- Characteristics of intellectually advanced young people
- Parenting Gifted Preschoolers
- NAGC's list borrowed from the book A Parent's Guide to Gifted Children
- Characteristics and Behaviors of the Gifted
- Characteristics checklist for gifted children
-Tips for Parents: Helping Parents Understand Their Profoundly Gifted Children
- Profiles of the gifted and talented which lists 6 different types, categorized by personality/temperament and achievement
- Bertie Kingore, Ph.D.: High Achieving, Gifted Learner, Creative Thinker? (hat tip to sanne)
- A common trait in gifted children, often listed amongst identifying characteristics, is alternately described as: "advanced moral reasoning", "well developed sense of justice", "moral sensitivity", "advanced ability to think about such abstract ideas as justice and fairness", "empathy", "compassion". Links to lists of gifted characteristics include several articles on the Davidson Database here and here, SENG (Silverman), SENG (Lovecky).
- ages at which gifted children may reach developmental milestones
- thread about Early Milestones - what do they mean?
- SENG video: The Misdiagnosis of Gifted Children
- book: Misdiagnosis and Dual Diagnoses of Gifted Children and Adults
- old post with link to article comparing gifted characteristics and ASD characteristics
- post with checklist comparing gifted and ASD traits (hat tip to BananaGirl)
- post with link to Gifted Resource Center of New England (GRCNE) article comparing gifted and ASD traits (hat tip to Nolepharm)