I hate to be a one upper but in Rancho Penasquitos, several years ago a 4 year old girl was given her Black Belt in Tae Kwon Do.
Hell, what's the point of being on an Internet discussion board if you can't indulge the pleasure of one-upsmanship every so often!
Her parents run a Sushi restaurant on Penasquitos Road just West of Interstate 15, It is called Sushi USA. They have a little shrine in the restaurant with news articles, and memorabilia of their daughters achievement. She is in High School now I believe, or possibly college.. I remember when that one happened, I was stuck between disgusted and laughter.
So assuming the standard 'test for X dan X years after the test for X-1 dan', she should, at say 17yo, be getting ready to test for her 5th dan. Time marches on eh? . She'll have her 7th dan when she's 34... nothing like an early start, eh?
I also have to mention that when I lived in the San Francisco Bay Area for a few years I went around and visited dozens and dozens of schools, and the one that I would say had the best fighters was a Tae Kwon Do school called Golden State Tae Kwon Do, with an instructor named Eddie Croft, who also happened to be a Championship Boxing contender.. who would have guessed.
No surprise there—boxers train for very close range fighting, which is where most streetfights happen to start, if a ton of research on what Pat McCarthy labelled 'habitual acts of violence' is on the money. Of all practitioners of combat activities, they seem to be the main ones who accept the unpleasant but realistic presmise that your attacker will be close in, and striking at your head and other high-valued targets with the intention of rendering you unconscious or dead, if possible. If more TKD schools organized their curricula around that premise, as advocated by 'applied karate' advocates like Iain Abernethy, Geoff Thompson, Peter Consterdine and other high ranking karateka some of whom also happen to have extensive experience as professional bouncers, the nature of TKD training would, I'd predict, lead to a lot fewer BBs for practitioners who can't tied their own shoe laces yet, let alone the belt itself. I think the McDojang belt-mill phenomenon, while separate from, is still linked to the dilution of the TKD curriculum to the point where its roots in hardcore street defense have become completely lost in many schools.