The most mythologized of the widely accepted sexual practices and the most widely accepted of the mythologized, the subject of endless sacred wars on forums and the favorite scare of homophobes who are not given by wives — anal sex, like any other area of human activity, has long become the subject of impartial scientific research.
According to statistics on the website of the famous Kinsey Institute for the study of sex, gender, and reproduction, 23% of women aged 20 to 24 engaged in anal sex in 2013. This age group is the peak of the normal distribution: as women move away from their early twenties, they practice this less and less. However, one in ten women do this both at 14-15 years old and after 70. Among men, as can be easily guessed, anal sex also varies. Even among the most successful age group in this regard, 25-29, only 27% inserted their partner’s member into the anus in the past year. In general, throughout life, only 40% of men and 35% of women have tried anal sex at least once – a classic situation from the joke “well, you’re talking about it.”
The popular myth that gays constantly engage in anal sex is also not entirely supported by statistics.
In 2011, Joshua Rosenberger and his colleagues from Indiana University studied the sexual practices of 21,288 homosexual men (and an additional 3,499 bisexual men). This extensive research found that during their last homosexual sexual encounter, approximately 35% of men engaged in anal sex in either an active or passive role, while approximately 75% performed or received oral sex and 63% engaged in mutual masturbation. In terms of overall sexual life, data indicates that anal sex is practiced by 75 to 90% of gay men from time to time.
The potential danger of anal sex stems from several components. Firstly, there may be mechanical injuries to the anus and rectum. Secondly, these injuries increase the likelihood of infection transmission if condoms are not used. Thirdly, even if there are no infections, semen entering the rectum can negatively affect the health and well-being of the receptive partner. To what extent are all these risks?
The degree of mechanical damage directly depends on the care of partners, the degree of arousal, relaxation, the amount of lubrication, etc. With anal rape, indeed, problems are almost inevitable – all (few) patients who were studied after this event at St. Mark’s Hospital in London had damage to the internal anal sphincter (a smooth muscle structure that we cannot control consciously), half of them also had damage to the external anal sphincter (the transverse-striped muscles that we control). This led to difficulties in controlling defecation. As for voluntary anal sex, problems are also possible but less frequent and less pronounced. In a study of homosexual men conducted at Pittsburgh University, it was shown that the degree of compression of the sphincter in a state of rest is indeed lower in those practicing anal sex compared to the control group. However, when the subjects were asked to specifically compress the sphincter, they did so with equal force in both groups and there were no complaints of pain.
The favorite scare of all moralists, hemorrhoids, develops for many reasons: improper diet, lack of physical exercise, pregnancy with its hormonal changes and increased pressure in the abdominal cavity, genetic predisposition, aging.
There are many panicked questions about the connection between hemorrhoids and anal sex on forums (none of them receive a clear answer).
On American medical websites for the general public, this connection is searched in the context of “if you had bleeding from the anus after anal sex, then you probably have hemorrhoids, see a doctor.” A search on scientific publications, such as Google Scholar, with queries like “hemorrhoids and anal intercourse” does not yield any normal, contemporary materials on the issue. Mostly articles about anal canal cancer and its connections with previous hemorrhoid history and anal sex are found. In this context, anal sex is not dangerous in and of itself, but as a cause of human papillomavirus infection, which causes both cervical cancer and therefore in recent years has been prevented through vaccination.
The main danger of anal sex is, of course, the transmission of infections. This form of sexual contact is more effective in transmitting viruses and bacteria than any other, and certainly much more effective than any other means of infection. Engaging in anal sex without a condom, a person agrees to receive all the good things that are in the body of their partner, from syphilis to hepatitis, from herpes to tuberculosis (this is not a typo; usually, indeed, Koch’s bacillus lives in the lungs, but about 5% of the time it chooses another organ as its main base, for example, the rectum). The good news is that the likelihood of infection after one unprotected sexual encounter is still far from 100 percent. The most calculations were done for HIV—it’s not the most contagious virus, but it is one of the most unpleasant. In its case, everything depends on the stage of the disease, the form of treatment, and, accordingly, the number of viral particles in the blood, but the approximate probability of infection is 0.8% per one vaginal act without a condom, and 1.4% per one anal act without a condom. It’s even safer than Russian roulette!
However, engaging in anal sex without a condom is not recommended even if you are absolutely monogamous and have been tested for all imaginable and unimaginable infections 100 times. Bacteria still live in the rectum, which can cause inflammation if they move up the urethra or are introduced into the vagina. This could be disregarded: urologists from the University of Melbourne note that a man can just as easily become infected with conditionally pathogenic organisms during vaginal or even oral sex if there is a predisposition. What’s worse is that semen entering the rectum is harmful to the recipient.
Semen contains a lot of prostaglandins. These hormone-like substances are actually called that because they were first extracted from the semen that is produced by the prostate. The physiological role of sperm prostaglandins is to stimulate the contractions of smooth muscles in the female reproductive tract, increasing the chances of conception. Many obstetricians even recommend having sex in the third trimester of pregnancy to prepare the cervix for delivery, although there is no solid experimental evidence to support this advice – women who do not have sex before delivery also give birth successfully. However, if there is a benefit in the vagina from prostaglandins, there is no benefit in the rectum.
First of all, there they also cause smooth muscle contractions which are often accompanied by unpleasant sensations – the victim of passion wants to go to the toilet all day. And secondly, there is experimental evidence that if prostaglandins enter the rectum, they may suppress the immune system. One of the main researchers of human sexual behavior, Scottish medical psychologist Stuart Brody, writes in his 2010 review that regular exposure to semen in the rectum leads to an imbalance in the optimal proportions between different types of lymphocytes in both sexes, ultimately leading to a clear suppression of immunity.
There, he tells a heart-wrenching story about rabbits, who for many days had sperm introduced into their intestines, and eventually it was proved that there was a complete imbalance in the immune system of everything that could only be. But these were male rabbits, and in animal experiments of both sexes, it still turns out that the negative effect is much more pronounced in males than in females. Basically, this is logical: women more often have to deal with someone else’s sperm, and the protective mechanisms that have formed for the mucous membrane of the vagina may partially work in the intestine as well. However, this is still a dark and mysterious molecular story, so it’s better not to check whether your wife is a rabbit or not, and use condoms just in case.
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