In addition to the team gold medal and He's gold on bars, Yang won bronzes in the all-around and uneven bars.
At a press conference in Beijing on Friday the IOC said that following fresh information it had asked International Gymnastics Federation (FIG) to look into the matter.
"We've asked the gymnastics federation to look into it further," IOC spokeswoman Giselle Davies said, without elaborating on the specifics of the information.
|China's women gymnasts won six medals in Beijing [GALLO/GETTY]
"If there is a question mark and we have a concern, which we do, we ask the governing body of any sport to look into it."
"You shouldn't regard this as some kind of formal investigation, but, yes we have asked the gymastics federation to look into what have been number of questions and apparent discrepencies on this subject," she said.
China's gymnastics coach meanwhile has insisted that all its gymnasts in the Beijing games were eligible to compete.
"The women athletes we had in these Olympics were in total compliance with the age requirement," Huang Yubin told a news conference.
"Since Asian bodies are not the same as Westerners', there have been questions. But there shouldn't be."
In an effort to remove doubts over He's age, on Thursday Chinese sports officials gave the FIG documents including her old passport, a residency card and her current Chinese ID card.
But several media reports in recent days have continued to question the veracity of those documents.
"Since Asian bodies are not the same as Westerners', there have been questions. But there shouldn't be"
Chinese gymnastics coach
One investigation turned up a photograph published last year by China’s state news agency Xinhua with a caption that referred to "13-year-old He Kexin".
There have been several cases of age falsification in gymnastics since the 1980s when the minimum competition age was raised from 14 to 15 to protect young athletes from serious injuries. It was raised again to 16 in 1997.
In 1993 North Korea was barred from the gymnastics world championships after FIG officials discovered that Kim Gwang Suk, the gold medalist on uneven bars in 1991, had been listed as 15 for three years in a row.
In 2002 Romanian officials admitted several gymnasts' ages had been falsified, including Olympic medalists Gina Gogean and Alexandra Marinescu.
With speculation mounting over the Chinese team since the start of this year's games, the FIG has said repeatedly that a passport is the "accepted proof of a gymnast's eligibility," and that China's gymnasts have presented papers that show they are age eligible.
The IOC has also said the girl's passports prove they are of competition age.