Penile Cancer: Another Reason to Stop Banging Animals: (Insert Zoophilia Joke)

ResearchBlogging.orgFirst up, I cannot believe the numbers! This is awe-inspiring. I read the abstract three times in order to convince myself that I was not seeing things. More than the results of the study itself what intrigues me no ends is how the researchers got the participants to open up about screwing with Billy. Billy as in Billy, The Goat. Not as in Billy Ray Cyrus, the father of Miley Cyrus… but then, on second thoughts. Oh. But I digress.


So, back to the awesome study. It was basically a case control study, here is a summary of it for the textually challenged (like me):


Now, much to the credit of the researchers, they had taken a long and hard look at the manner in which the subjects had indulged in their fetish. Here are some of the aspects that they uncovered:

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Now, a few of the points that strike me while reading the abstract:

  • About 1 in 3 men admitted to having sex with an animal overall, and in my view that is quite a high percentage. The study was done in 16 Oncology clinics in Brazil and despite the main matter at hand, also raises the question how they got the people to open up. Bestiality is usually explicitly or implicitly an illegal act and admitting to it comes with its own package of social and cultural connotations. So, despite the interesting results, the why and the wherefores of the high rate of SWA is a striking matter.original
  • The main paper is not available on the site right now, in fact, the site has been unreachable for the past couple of hours, and I am wondering if the publication of this study broke the site with traffic! So, I cannot look at the data in more details than this. I was especially interested in looking at the demography of the participants and note of there was any rural-urban divide in the rates of SWA. Logically speaking, there should be, as should be a socioeconomic gulf in the rates as well.
  • Some pathophysiological considerations for the slightly increased risk of penile cancers in people who have sex with animals might include:
    • Microtrauma to the penile tissue during sex with animals.
    • The microtrauma might be further exacerbated by the fact that there would be extensive difference in the texture of the tissues of animal mucosa with respect to the human one.
    • The difference in the chemical nature and pH of the secretions of the animal mucosa might also be a contributory factor.
    • Since animals are not known to practice safe sex while having sex with other non-human animals, it is likely that they harbor potentially oncogenic infectious agents, which, probably in an HPV-like manner contribute to the increased risk of penile cancer in the fetishists.

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There are several other factors, like the socioeconomic bearing, unprotected sex with (human) prostitutes and group sex that might add to the burden caused by the issue of having sex with animals. However, even in multivariate analyses, the results have come out to show that sex with animals still has a significant contributory factor in causing an increased rate of penile cancer in men.elephant sex

Although I would like to believe that sexual contact with animals were stopped once they started having sex with human beings, the numbers tell a different tale. And to be honest, the study size overall is pretty small. A study run for a longer time, over more centers and more rigorously controlled might provide better data. I find the 35% rate of sex with animals overall to be unbelievably high!

Anyways, the study seems methodologically valid and statistically rigorous. The research question is stupendously mind blowing. The multi-centeredness probably gives a good geographic spread to control for any local causes. And of course, the pathophysiology behind the study results, the core science, seems sound on principle.

So I guess it is time to stop having sex with animals now that the association with such a dangerous disease has been proved beyond a shade of doubt?



Zequi SD, Guimarães GC, da Fonseca FP, Ferreira U, de Matheus WE, Reis LO, Aita GA, Glina S, Fanni VS, Perez MD, Guidoni LR, Ortiz V, Nogueira L, de Almeida Rocha LC, Cuck G, da Costa WH, Moniz RR, Dantas Jr JH, Soares FA, & Lopes A (2011). Sex with Animals (SWA): Behavioral Characteristics and Possible Association with Penile Cancer. A Multicenter Study. The journal of sexual medicine PMID: 22023719

Get That Heroin Rush, Safely

ResearchBlogging.orgClinical observations and lesion based studies have long shown that the brain is an important adjunct for sexual functions. Although the role of the brain in ejaculation and orgasmic sensations is not well understood, the impairment of these functions in patients with strokes or parkinsonism have long shown that the brain has some role to play in it.

In this study, the researchers used positron emission tomography to identify the areas of the brain which showed increased regional cerebral blood flow during ejaculation in 11 male subjects, who were brought to climax by manual penile stimulation by their female partners. I was of the opinion that an fMRI was a more sensitive way to understand which areas were getting activated/deactivated during the process of ejaculation, the authors make a compelling point in favor of using PET: the high sensitivity of the fMRI would itself be a bane in the study where there were too many extraneous motor noise sources anyways!

As expected, there are so many parameters that can cloud the results of the findings in such a study, given how multiple sensory stimulations are involved in the process of sexual arousal and ejaculation. However, the manner in which the researchers tried to control the experiment and minimize the “noise” in the data, is an interesting read in itself. Let us take a brief look at some of those measures:

  • To minimize extraneous motor signals, the study volunteers were stimulated by their female partners.
  • The tactile penile stimulation was continued even after ejaculation so that there were no confounding features.
  • The volunteer’s head was restrained with an adhesive band.
  • To minimize the visual inputs, the volunteer was asked to keep his eyes closed. How this works is difficult to gauge, since some form of visualization is bound to happen.
  • The volunteers were extensively coached in the process and were asked to practice a week in advance. There can be few other incentives which are more appealing to man to give his self for the advancement of science.
  • The volunteers said that there were no significant difference in the sexual pleasure they experienced under normal circumstances and under the scanner. (I can only assume they were habituated to get hand-j*bs while their heads were tied down, eyes shut, while a bunch of scienctists looked at colorful pictures of his brain and shouted out when he could have a go).

Anyways. Eventually, 5 of the volunteers ejaculated once, 3 twice, and 3 did not manage to make any positive contributions to the results of the experiment. The ejaculations were timed with respect to gaining the most out of the time frame for the PET scan to bring home the results and out of the 11 ejaculations, 8 could be timed and were used for the purposes of the study.

On analysis, the strongest activation was found in the Mesodiencephalic junction. One of the areas of the activated portions is the ventral tegmental area. It is this portion of the brain which is responsible for several reward mechanisms being set off in motion, including the orgasmic effects of cocaine or heroine (coke/heroin rush) (1). Hence, it would not be out of place for the same area to be activated during ejaculation following manual tactile sexual stimulation by a partner.

Another area which seemed to have been prominently lit up is the cerebellum. Although it is possible that the movements by the volunteers maybe responsible for part of the activation, it has also been implicated in being a part of the heroin rush phenomenon (1). It is also in line with lesion studies that have shown an emotional flattening and increased risk taking following cerebellar damage, which indicates that it does have a role to play beyond motor coordination.


Figure 8. Activations in the cerebellum, brainstem, and occipital cerebral cortex. Increases in rCBF are superimposed on the averaged MRI of the volunteers and are depicted in oblique (45°) sections (see the red lines on the glass brain on the left). Cerebellar activations can be observed in the vermis (v; sections b-h), the cerebellar hemispheres (ch; sections d-h), and the deep cerebellar nuclei (dcn; sections b-d). Note that activation in the cerebellar hemisphere is more pronounced on the left than on the right side. Brainstem activation is present in the medial pontine tegmentum (section a), the lateral pontine tegmentum (sections b and c), and in a region possibly involving the dorsal vagal nuclei and the solitary complex (sections f and g). pt, Pontine tegmentum; r, right side.

One more interesting finding was the medial preoptic area (MPOA), which has been seen to be critical for sexual activities in rodents, was not activated. Since a lot of early sexual neurobehavioral studies and lesion studies were conducted on the rodent model, this might be an interesting offshoot. Since the human nervous system is significantly more complicated than the rodent’s, this would mean that there may be areas which need reexploration if the MPOA inactivation is seen to be a prominent occurrence.

Notably, of the neocortical regions, only the right sided Brodmann’s area was activated. This is in line with the expectation that as a primal instinct, sexual stimulation would be more a matter of the older segments of the brain. And sometimes, it is small things like these which make me wonder at the marvel that is the human body. There can be no man made machine that can be as finely evolved and balanced, and of course, shrouded in mystery, as the human brain itself.

Another interesting finding, which was, however, more predictable, was the fact that there was significant deactivation of the amygdala and the entorhinal complex. It is med school neurophysiology MCQ knowledge that the amygdala is involved in the mediating fear and vigilance, and hence a deactivation of this area with sexual stimulation seems appropriate. Since the times immemorial, how many men were taken down in their vulnerable moments by women who were clever enough to get them to lower their amygdalic defenses? Understandably, this area is also deactivated during cocaine rush (1). Thus, mediation of euphoric states seems to be accompanied with an inactivation of the amygdala.

Although my understanding of the complex neurological response to psychological manipulation is little, it is safe to say that despite such a well controlled test, there still remain a lot of unanswered queries. For example, what exactly are the implications of the cerebellar activations? More details on the absence of activation of the MPOA and bed nucleus of the stria terminalis (BNST), which have been traditionally seen to be important areas mediating sexual activities in rats is needed. If there are differences in the functioning of this area between rats and humans, how significant is it? Would it mean that some older perspectives need to be reassessed in the light of this information?

I think this is an interesting study and for the first time, it lends some credibility to the long held female notion that all men have sex on their brains.



Sell LA, Morris J, Bearn J, Frackowiak RS, Friston KJ, Dolan RJ (1999) Activation of reward circuitry in human opiate addicts. Eur J Neurosci 11: 1042-1048.[Web of Science][Medline]

Study in Focus:

Holstege G, Georgiadis JR, Paans AM, Meiners LC, van der Graaf FH, & Reinders AA (2003). Brain activation during human male ejaculation. The Journal of neuroscience : the official journal of the Society for Neuroscience, 23 (27), 9185-93 PMID: 14534252