The Drs. Eide have an interesting post titled 'Is Prodigy a Myth?' They make a point that individual children, and I'll add all people, learn at different rates, and I would indeed have to argue that there are "late bloomers" who do not reach their learning stride until later years in school. I don't think prodigy necessarily shows its face at very young ages, but can in some cases begin in later years, meaning middle or high school years. Is this a product of practice, or is there innate ability that develops in the appropriate environment? I think we'd be wise to consider both...the brain is a complicated creature, and there is a broad range of possible outcomes and developments for individuals.
This also falls back to an argument I have made in the past about the American education system, and why I wish we'd not fall into a type of testing fixation (i.e. a test meritocracy) as our definition of learning or academic success...we need variety in schools, and we need to expose children to all subject areas over their entire schooling career so they can find what interests them and provide choices for what to take on and study in later years. I suspect giftedness and prodigy will continue to be debated forever, but my experience leads me to conclude that we must continue to allow individuals to have choice and the ability to 'play the field' of academic areas of study in order to find their own place in society, and where they want to focus their energy and effort. And we should resist the notion that every individual will find that area of study or interest at an early age, and allow those who do happen to develop in the high-age tail of the distribution a chance to do so. I've had students who did not flourish intellectually until late in high school or even in college (and their achievement prior to that on standardized tests as well as school grades suggested average or below average ability), and they ended up excelling once their intellectual skills, interest and motivation caught up with their age. I should metion that this notion is supported by brain research. For example, the highest IQ children tend to fully develop the prefrontal cortex of the brain at later ages (~11 years of age) than average IQ children. This tends to lead to more immature behavior, which may in turn mean they do not perform (or be allowed to perform, if classified as ADD or something similar) in class as a high-IQ individual until they are older. So biologically, some high-IQ kids are late bloomers. We need to be aware of this.