Someone I know is teaching her (just) 3 year old to read. Not because the 3 year old is wanting to do so AFAIK, but because the mum thinks it will give her a head start when she start school.
I deliberately didn't teach my DS (now in Reception) on the basis that I'd rather he did it at the same time and in the same way as his class mates. Although TBH there's no way he would have been receptive to formal teaching anyway and I'd probably have scared him off reading or life.
Are there any specific advantages (or disadvantages) in teaching a pre-school child to read?