That, at least, is what a group of pediatric endocrinologists concluded from a study of more than 500 Playboy centerfolds.

"So often these people get convicted on what I refer to as felonious bad taste," said Dr. Arlan Rosenbloom, a pediatric endocrinologist at the University of Florida in Gainesville. "They're downloading stuff that isn't very nice, but isn't illegal."

In many cases, prosecutors are basing their cases against people who have downloaded images, and don't have a way to confirm the subjects' ages.

In a study published online today in the journal Pediatrics, Rosenbloom and his colleagues write that they were prompted to examine "547 images with breast exposure from an anthology of the monthly centerfold illustrations in Playboy magazine from December 1953 to December 2007" because Rosenbloom had seen the so-called Tanner scale misused in trials.

The scale, published in 1969 by Dr. James Tanner and a colleague, describes five stages in the development of male and female sexual characteristics such as the shape of breasts and presence of pubic hair. Stage 5 is referred to as "mature," leading to some confusion over whether all women over 18 were in that stage.

The authors chose Playboy centerfolds because publisher Hugh Hefner is known for being scrupulous about only having models over 18. (The study may be the only one in the scientific literature to cite 2007's "Playboy; The Complete Centerfolds.")

When four pediatric endocrinologists looked at the centerfolds, however, at least one of them thought more than a quarter were Tanner stage 4. That kind of evidence, argued Rosenbloom, who has testified on behalf of defendants in such cases, has been used to bring people to trial and even convict them, based on the false idea that all women over 18 were Tanner stage 5.

"I thought it was important to let the pediatric public know that this is not an appropriate distinction," Rosenbloom, who has a related paper coming out soon in the International Journal of Legal Medicine, told Reuters Health.

‘WHOLLY ILLEGITIMATE USE'

Tanner himself - who died in 2010 - acknowledged in a 1998 letter co-authored with Rosenbloom that judging a person's age based on the stages that bear his name is a "wholly illegitimate use."

"Physical definitions of ‘child' are inherently problematic," Richard Wortley, a professor at University College London and co-author of "Internet child pornography: Causes, investigation and prevention," told Reuters Health by email. A recent court case, for example, "ruled that pictures that 'appear to be' of a minor was too imprecise, and that chronological age should be the criterion. Internationally most legislation is based on chronological age."

Yaman Akdeniz, a law professor at Istanbul Bilgi University and the author of "Internet Child Pornography and the Law," said most child pornography cases involve images of "younger children under the age of 12 rather than older teenagers." In such cases, distinguishing between Tanner stages 4 and 5 would be irrelevant.

However, he told Reuters Health by email, "courts deal with some contested cases in which the age of the person appearing in such images is questioned." How often the Tanner scale is used, however, is "very difficult to say," he said, noting that it should not be the only evidence to determine guilt.

The paper makes a good case against using Tanner stages in child pornography cases, according to Chuck Kleinhans, of Northwestern University's School of Communication in Evanston, Illinois.

But Kleinhans, who has studied child pornography issues, noted in an email to Reuters Health that the Playboy Playmates are "carefully groomed and have full body makeup before they go in front of the cameras." They're also "very carefully posed and lit," and "famously retouched (airbrushed) and modified before publication."

"Given contemporary Photoshopping technology, centerfolds are completely different from clinical medical photography, especially for forensic purposes," he said.

Rosenbloom acknowledged that the centerfolds were hardly the perfect set of data. He noted, however, that if anything, given that they tended to be well-endowed, they biased the sample against his claim, strengthening the conclusions.

The study, after all, looked at how often an "expert" might consider breasts to be at stage 4, he said; it was not designed to determine how many women had breasts at that stage. "For that you would need to have clinical grade photos or at best, examination of at least 100 young women, not an easy task."

SOURCE: bit.ly/R2SA71 Pediatrics, September 3, 2012.

• A Permanent Economic Emergency