Evidently the IOC goes by the age listed on the athlete's passport which gives her date of birth as January 1, 1992, but the CDT has found a number of news articles and other documents that suggest that Ms. He's date of birth is in fact January 1, 1994. If the passport date of birth has been falsified this would suggest Chinese Government collusion in this fraud (most likely without the knowledge of senior level Communists).
This unexpected incident has enormous explosive potential as Chinese people everywhere who are so proud of China's hosting of this important international event will feel great loss of face if He Kexin has her gold medal taken away. It will be much worse than when Canadian Ben Johnson was revealed to be a cheat at the '88 Olympics and lost his medal. "Face" is such strong imperative in Chinese culture.
I also feel sorry that the matter involves a child who will suffer stigma for the rest of her life, despite being too young to be held in any way responsible for the alleged fraud, if it turns out to be proven definitively that she is in fact underage for the competition.
The whole thing is just so regrettable.
Update October 1, 2008: The IOC has ruled that the who competed at this year's Beijing Olympics were not underage: http://news.yahoo.com/s/nm/20081001/ts_nm/us_gymnastics_china