Blanchard has published this work online, making the work freely available to all comers. Click here to see the full paper. But, because this work is so important (the scientists assembled in Canada were stunned into near silence when they saw the impressive datasets and theoretical work Blanchard put before us), I asked Blanchard to explain the work somewhat more plainly for those who are not scientists. He’s been kind enough to do so for us here.
Blanchard explains first the laboratory method used:
“This dataset included measures taken with the same laboratory method used by Freund et al., namely, phallometric testing. Phallometric testing (sometimes called penile plethysmography) is an objective technique for assessing erotic interests in men. In phallometric tests for gender and age orientation, the individual’s penile blood volume is monitored while he is presented with a standardized sequence of laboratory stimuli depicting male and female children and adults. Increases in the patient’s penile blood volume (i.e., degrees of penile erection) are used as the measure of his attraction to different classes of persons.”
In other words, sex researchers studying these men strap a device over the subjects’ penises to measure how swollen or flaccid their penises become in response to various kinds of pictures and audiotapes. The idea is that, the more erect the penis, the more the man has been stimulated by the particular sexual material being presented to him. Blanchard further describes the subject population of his recent study:
“The subjects were 2,278 male patients referred to a specialty clinic for phallometric assessment of their erotic preferences. All underwent the same test, which measured their penile responses to six classes of stimuli: prepubescent girls, pubescent girls, adult women, prepubescent boys, pubescent boys, and adult men. The stimuli were not, of course, live persons, but rather audiotaped narratives describing sexual interactions with prepubescent girls, pubescent girls, and so on. These narratives were accompanied by slides showing nude models who corresponded in age and gender to the topic of the narrative. The slides did not show the models doing anything sexual or even suggestive but rather resembled photographic illustrations of physical maturation in a medical textbook.”
Some laboratories doing phallometric tests use a “strain gauge,” which is just what it sounds like: a sensitive wire strapped around a penis to measure how swollen a subject’s penis gets in circumference in response to various stimuli presented to the subject. But Freund’s and Blanchard’s groups used a more precise type of measurement, a kind of bell jar that goes over the whole penis and allows the researchers to detect even small changes in penile volume. Blanchard explains:
“Penile responses were recorded as cubic centimeters (cc) of increase in penile blood volume from the time a stimulus trial started to the time it ended. (A stimulus trial was one audiotaped narrative plus slides.) A full erection, as measured by the equipment used to collect these data, would typically correspond to an increase in penile blood volume of 20-30 cc. However, most subjects responded much less than that.”
So what the researchers were looking at was relative stimulation to different kinds of sexual materials, some suggesting sexual encounters with prepubescent girls or boys (usually about aged 10 and younger, and of sexual interest to pedophiles), some suggesting sexual encounters with pubescent girls or boys (generally aged 11-14, and of sexual interest to the group termed “hebephiles”), and some suggesting sexual encounters with sexually mature men and women (of interest to the people researchers call “teleiophiles,” and what the rest of us tend to call “normal,” i.e., “straight men and women,” “gay men,” or “lesbian women”).
In Blanchard’s work, the subjects were assigned to one of six groups according to their highest response on the phallometric test: (1) men who responded more to adult women than to any of the other five stimulus categories were classified as heterosexual teleiophiles; (2) men who responded more to adult men than to any other stimulus category were classified as homosexual teleiophiles; (3) men who responded more to pubescent girls than to any of the other categories were classified as heterosexual hebephiles; (4) men who responded most to pubescent boys, were classified as homosexual hebephiles; (5) men who responded most to prepubescent girls were classified as heterosexual pedophiles; (6) and men who responded most to prepubescent boys were classified as homosexual pedophiles.
So what did the numbers in each category look like? First, keep in mind that this is not a random sample of the population walking around cities; this is a sample of men who were specifically referred for testing, typically because they were suspected of a crime or sought therapeutic help. Among that group, “the procedure of classifying subjects according to their highest penile response produced 1,066 heterosexual teleiophiles, 761 heterosexual hebephiles, 159 heterosexual pedophiles, 110 homosexual pedophiles, 86 homosexual hebephiles, and 96 homosexual teleiophiles.”
In order to repeat Freund’s comparisons for this post, Blanchard graphed the relevant information from the dataset as shown in the accompanying figure. He notes, “This figure shows the mean (average) response of each group to each stimulus category. So that statistically inclined readers can make some comparisons besides those I will explicitly discuss, I have included the 95% confidence interval for each mean. These are represented by the vertical lines bracketing the top of each bar. Two means are significantly different if their confidence intervals do not overlap. The converse, however, is not true, and the significance of the difference between means with overlapping confidence intervals must be tested with methods other than visual inspection.”
So what does this pretty picture mean?
Blanchard explains: “The key comparisons produced results similar to those of Freund et al. They show that gay men (homosexual teleiophiles) and straight men (heterosexual teleiophiles) have similar penile responses to depictions of children in the laboratory,” that is to say, relatively low. But more important than their being relatively low, they’re not really any different for gay and straight men.
Furthermore, “The responses of heterosexual teleiophiles to prepubescent girls were similar to the responses of homosexual teleiophiles to prepubescent boys (gold bar in top left panel vs. green bar in top right panel). The difference between these means was not statistically significant. The responses of heterosexual teleiophiles to pubescent girls were actually slightly higher than the responses of homosexual teleiophiles to pubescent boys (orange bar in top left panel vs. blue bar in top right panel). This difference was statistically significant; however, it is most likely trivial, because the heterosexual teleiophiles were generally a little more responsive than the homosexual teleiophiles.” So it doesn’t look like gay men are any more likely than straight men to be attracted to pubescent children.
Finally, “The middle panels and bottoms panels of the figure show that the stimuli depicting pubescent and prepubescent boys and girls worked as they should. The subjects who responded most to those stimulus categories responded as much or more, in absolute terms, as the subjects who responded most to adult men and women.” In other words, we have reason to believe that this testing method is giving us real data when we use it to conclude that gay men are no more likely to be sexually interested in children than straight men are.
One more thing Blanchard asks us to keep in mind: “Although the purpose of this analysis was to counter the notion that gay men present more of a risk to children than do straight men, it was not intended simultaneously to demonize all pedophiles and hebephiles. There are pedophiles and hebephiles who never act on their sexual attraction towards children. They cannot be blamed for what they feel, and they should be supported for the constant self-restraint they must exercise in order to behave ethically.”
Indeed, Blanchard’s work suggests to me that pedophilia and hebephilia look like sexual orientations; in other words, at least for men, sexual orientation is comprised not just of interest in a particular sex, but in a particular age range as well. That doesn’t mean, of course, that adult sexual interactions with prepubescent or pubescent children are morally permissible or should be legally permissible; Blanchard and I both feel that pedophiles and hebephiles have a duty not to act on their sexual urges, because children cannot meaningfully consent to sex with an adult. It is just to say that it makes no sense to persecute someone for an urge on which he does not act.