X-rays good as gold in telling age

How do you tell the age of a Chinese gymnast?

Don’t bother with those government-issued passports or birth certificates.

Go for the X-rays.

For all the global hand-wringing over how international gymnastics officials will ever figure out whether three members of the Chinese women’s team were old enough to compete, doctors and forensics experts said it’s actually not too difficult.

The science of determining age is has been honed by decades of treating patients with growth disorders, identifying youthful homicide victims and determining the deportation status of illegal immigrants.

“It would be relatively easy,” said Dr. David Senn, a forensic odontologist at the University of Texas Health Sciences Center who has analyzed numerous X-rays of immigrants apprehended at the border.

The science is based on measuring the growth of bones and teeth as children mature. Decades of data have been distilled into detailed tables recording the precise size and shape of skeletal components broken down by age, sex and race.

The task is so straightforward that Dr. Peter Hampl, president of the American Board of Forensic Odontology, said the Chinese government should just consent to X-rays and let the films speak for themselves.

“If there is nothing to be afraid of, let their kids be X-rayed,” he said. “It’s almost incriminating if they don’t.”

It may seem strange that amid the outsized pageantry of the Beijing Games, the biggest controversy has surrounded three tiny Chinese gymnasts whose combined weight is 216 pounds.

The ages of He Kexin, Yang Yilin and Jiang Yuyuan came into question weeks ago after the discovery of online registration records listing birth dates that would make all three girls 14 years old. Olympic rules require that a gymnast be at least 16 during the year the Games are held. The government attempted to put the issue to rest by producing passports that declared the girls met the age requirement.

The controversy reached Olympian proportions after the Chinese team beat the American gymnasts in the team competition. In addition to the team gold, He edged American Nastia Liukin for the top prize in uneven bars by a tiebreaker, and Yang won the bronze medal in that event and in the all-around competition.

After new complaints surfaced, the International Olympic Committee announced Friday that it was asking the International Gymnastics Federation to reexamine the Chinese gymnasts’ age.

Instead of searching through documents, the matter could be settled with X-rays, said Dr. Gil Brogdon, a professor emeritus of radiology at the University of South Alabama in Mobile and author of the textbook “Forensic Radiology.”

Bones fuse together according to a well-documented schedule. For girls between the ages of 13 and 17, the best places to look are the knee, wrist, elbow and iliac crest on the pelvis, he said. The younger they are, the more obvious the evidence.

“A Caucasian girl is going to fuse her knee centers at about age 15; they’re going to fuse their iliac crest at about age 16; and part of the elbow will start fusing around 13 or 14,” he said. “That’s the way you do it.”

For the Chinese gymnasts, investigators would have to consult growth tables for Asian girls, Brogdon said.

One complication with teenage girls is that strenuous exercise can suppress estrogen production, delaying bone development and making them appear to belong to a younger person, said Dr. Vicente Gilsanz, a professor of radiology and pediatrics at USC.

But Brogdon said that by comparing multiple bones, “you could come pretty close” to distinguishing a 14-year-old from a 16-year-old.

Teeth are also useful. U.S. immigration authorities often rely on dental X-rays to determine for deportation purposes whether an illegal immigrant is an adult or a minor.

“Of course, everybody who gets arrested says they are 17,” Senn said.

He said he can pinpoint ages within 18 months using images of a person’s wisdom teeth, which start forming around age 9 and are not fully developed until around 19. For the Chinese gymnasts, Senn said, he would also look at their second molars, which grow until age 15 or so.

Dr. Michael Baden, chief forensic pathologist for the New York State Police, said that with both teeth and skeletal X-rays, “you should be able to get within 12 months” of someone’s age.

All this science probably won’t mean much because Chinese authorities are not likely to agree to let independent doctors take X-rays of their gymnasts.

In that case, sports fans will be left to contemplate the girls’ physical appearance.

“I must say, they do look kind of young,” Baden said.

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karen.kaplan@latimes.com

alan.zarembo@latimes.com

Times staff writers Mary Engel and John Johnson Jr. contributed to this report.