Child porn evidence unreliable: study of Playboy

A commonly used method of judging a woman's sexual maturation may not be good enough in child pornography prosecutions.

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."