There are better sources than that on precocity in young children. I'll have to find some references for you. (They may not be found in time for the edit window of this comment, so feel free to write me off-forum if you would like those.)

In general, early reading is less remarkable (in English) than people think it is, because with the right materials[1] English can be seen by a young learner as a rather consistent writing system that is not insuperably hard to decode.

That said, my four homeschooled children, the first two of whom are strongly bilingual in Chinese and English, having lived in Taiwan in early childhood, were early but not strikingly precocious readers, and all my children were learning a lot of other things besides reading in their early childhood, of which chess was perhaps more conspicuously precocious than reading. Earliness is less important than long-term solid development of skill, and it sounds like the parents of some of the HN participants here who have personally observed examples of very precocious reading were well aware of that.

[1] http://www.amazon.com/Teach-Your-Child-Read-Minutes-ebook/dp...

http://www.amazon.com/Lets-Read-Linguistic-Leonard-Bloomfiel...

http://eps.schoolspecialty.com/products/details.cfm?serieson...

A friend of my sons comes from a house definitely not focussed on teaching reading and writing at a young age. Yet their 5 year old son is streets ahead of his age for reading and writing. He is naturally gifted at it. None of his siblings share this trait or even an interest.

Another friend of mine found out their son was a reader when he started kindergarten. He was always 'reading' the books in the house, but his parents thought he had just memorised them from being ready. In fact his kindergarten teachers gave him new stuff to read and he lapped it up. He was reading the first Harry Potter book by the second grade. My friend actually got frustrated because his son didn't want to do father/son things, but preferred to read.

Some kids are gifted readers, just like some are gifted at hitting a ball with a bat. The important thing is (a) spend extra time and attention if it is clear they do have a gift and (b) don't feel like your child is somehow behind if there is a kid like this in their class.

Science tells us that it's not either/or, it's the interaction between our genes and the environment.

My intuition (based on anecdotes and observations, not hard data) is that nature provides a starting point, and perhaps an ultimate cap or speed limit to growth, but nurture provides the year over year progress. The most successful people I know nailed the nurture (or hard work) part of the equation. They were all at least smart, but very few were the smartest in the room at a young age. Over time they've appeared smarter and smarter to their surrounding audience.

I have twins. It's nature, shaped by nurture.

Identical? I've observed fraternal twins whose parents try to raise them 100% identical, but have wound up very similar in values but different in abilities and personality.

Nature vs nurture is a fun topic. The above topic reminded me how I learned to read. No where near as advanced as they, but nightly my dad would read to me and often the same book, the little prince. I was four or younger. I noticed that the words correlated with what is said, and I began seeking forward for shorter two and three letter words and was excited when I acurately picked out the right upcoming words. The words got bigger and I realized the link between letters and sounds. Exposure is important. Related somewhat to the article: my first memory is around 18 months old and involved knowing a good guy toy was to be punched and I found it odd that you would "hurt" the good guy.