Criticism of Pope Benedict’s recent remark on the effectiveness of prophylactics fails to distinguish between the moral and physical aspects of using such devices. As the supreme teaching authority of the Catholic Church, the Roman pontiff is concerned mainly with the moral aspect of venereal disease transmission. Condom usage fails to address the moral cause of sexually transmitted disease – namely, promiscuity – and indeed may encourage it by creating a false sense of security. In this sense, prophylactics are not a solution to the problem, but may even exacerbate the problem.
Many commentators have misconstrued the Pope’s statement as making the untenable assertion that condoms are physically ineffective. While it is unquestionable that prophylactic devices significantly reduce the chance of infection, there are sound statistical reasons for doubting their ability to contain epidemics. We will examine these reasons briefly, to show that condoms, to some extent, fail as a solution to the STD problem even in a physical sense.
According to the FDA, when condoms are used properly and consistently, the rate of pregancy in one year is 3%. Based on actual use, with human error and negligence, the pregnancy rate with condoms is 14% in one year. Without protection, the pregancy rate is 85%, so the figures cited reflect condom failures in 3.5% of optimal users and 16% of actual users in a given year. However, we must also consider that those who became pregnant likely had multiple failures in that year, since it is difficult to become pregnant on the first attempt. Even with optimal fertility (25%) it typically takes 4 months, so those who became pregnant likely had 4 or more failures per year. Assuming a Poisson distribution of failures, this means there’s an average of 1.25 failures per year with optimal usage, or 2.25 failures per year based on actual usage.
Again using Poisson statistics, I compute from the above that the chance of one or more failures per year is over 70% based on optimal usage, and nearly 90% based on actual usage. Based on the U.S. average of 58 acts of intercourse per year, there is a 2% failure rate per act with optimal usage, and a nearly 4% failure rate with actual usage. These results are consistent with other studies showing that condoms slip off completely 1-5% of the time.
In a society where the prevalence of STD is low, the failure rate of prophylactics is low enough to provide adequate protection, since it is improbable that a failure will occur while with an infected partner. However, in many African countries, the prevalence of AIDS and other STDs is in the range of 10-20%. This makes it a statistical near-certainty that a person will acquire that disease in a decade or so, if partners are changed constantly, even if condoms are used properly and consistently. Thus condoms are not an effective solution to the STD problem in high-prevalence areas like Sub-Saharan Africa.
People can minimize their risk even in high-prevalence areas by remaining monogamous with a partner who is known to be uninfected. In this scenario, multiple prophylactic failures pose little or no additional STD risk. A promiscuous person, by contrast, is exposed to the full risk of the high prevalence rate in the general population. This risk can be reduced by having one’s partner tested in advance, but the clandestine and spontaneous nature of promiscuous encounters operates against the likelihood of such precaution.
These theoretical expectations are corroborated to an extent by the actual epidemiology of STDs. In the United States, more than 50% of AIDS cases are among homosexual males, a tiny subgroup (3% of men or 1.5% of adults) where extreme promiscuity is common, and having as many as 100 partners per year is not rare. More than half of all syphilis cases in the U.S. are in the South, particularly among blacks, where promiscuity among the youth is rampant, and 48% of black women aged 14-19 have an STD. Still, in most cases, the prevalence of disease is low enough for prophylactic use to contain its spread. Such is not the case in Africa, where adultery and prostitution are practiced with much greater frequency than in the West, enabling AIDS to become an epidemic in the heterosexual population.
The relationship between behavior and epidemiology is not always straightforward. For example, in the United States there was an eightfold increase in genital warts in females from the early 1950s to the late 1970s (rising from 13 to 106 per 100,000). Gonorrhea incidence rose to epidemic proportions in the 1970s and 1980s. These changes are generally attributed to the liberalization of sexual attitudes, leading to greater promiscuity. However, an infectious disease is caused by an organism, so it may be influenced by biological factors, as seems to be the case with the gradual decline of gonorrhea in Europe and Israel since 1970, as well as its resurgence in the late 1990s.
Still, the ability to contain STD transmission through the usual means of prophylactics seems ineffective in the long run when not accompanied by more fundamental changes in behavior. In the U.S., where condoms and sex education have been ubiquitous for decades, 65 million people have viral STDs. (American Social Health Association (1998), “Sexually transmitted diseases in America: How many cases and at what cost?”) Over 50 million of these have genital herpes (Fleming DT et al. (1997), “Herpes simplex virus type 2 in the United States, 1976–1994,” New England Journal of Medicine, 337, 1105–1111. NIAID estimates range from 45-60 million.) Considering the entire U.S. population aged 14 and over is 242.9 million (in 2006), this means about 27% of the postpubescent population has a viral STD, and 21% has herpes. If this is success, what does failure look like? Faced with these facts, only the hardhearted could deny that even a highly developed “safe sex” public policy is unable to contain STDs in the long run.
Indeed, with the prevalence of herpes exceeding 20% in the U.S., condoms can no longer serve as an effective means for containing the epidemic, because their failure rate is not low enough to stop the spread of the disease among promiscuous people. With an average of at least 1-2 failures per year even when used properly, it is only a matter of time before someone with multiple partners in an exposed community becomes infected. This is not to say that condoms are altogether ineffective, but they can only slow the epidemic, not stop its spread.
Emphasis on condom use rather than reforming behavior is predicated on the assumption that it is difficult or undesirable to get people to change their sexual behavior. However, the entire enterprise of promoting prophylactic use involves getting people to do precisely that. There is no reason in principle why the same educational effort could be applied to encouraging people to at least limit their number of partners, if they cannot be absolutely monogamous. When sexual disease is highly prevalent, it is utterly misleading to claim that promiscuous behavior is “safe sex” when condoms are used. Risk is best minimized by knowing one’s partner well, and limiting changes in partners as much as possible. While this should be obvious, it has not received due emphasis in public health education. This reticence may be grounded more in the liberal sexual morality of policy makers and educators than in sound reasoning.
It has been known for ages that promiscuity is at the root of “social diseases.” Historically, these diseases had been marginalized in Europe and her colonies, confined mainly to the indecent practitioners of prostitution, adultery and fornication. With the destigmatization of these practices, sexual disease has gone into the mainstream, and will likely remain there as long as people fail to maintain a salutary monogamy, or at least a very limited polygamy. Long-term monogamy or limited polygamy has been the dominant paradigm of most human cultures for good reason, and has survived the test of experience. It is bad policy not to discourage foolish behavior, and even worse to tacitly encourage it, by claiming that it can be made safe.
Modern Western medicine has become notoriously negligent in addressing the behavioral causes of disease (e.g., nutrition, exercise, sleep), and instead increasingly emphasizes the use of expensive drugs and devices to address maladies after the fact. We see the same approach with sexual diseases: the solution is in a device that can be bought and sold, rather than in correcting behavior, which costs nothing, but requires patience and a modest amount of discipline.
None of this implies that prophylactics play no role in solving the STD problem, for they do indeed reduce the rate of transmission. For this reason, many contend that it is injurious for religious organizations like the Catholic Church to oppose the use of contraceptives, and effectively encourage the spread of disease. However, the same religions that oppose contraceptives also condemn adultery, fornication, and prostitution in even harsher terms. It is hard to believe that there are people who would have no qualms about committing the major offenses of adultery, fornication or prostitution, yet scrupulously heed their church’s strict teaching against contraception while committing those acts. Those who flout their church’s teaching on marital fidelity will almost certainly have no scruples about using contraceptives.
This appears to be borne out by religious statistics: only 20% of nominal Catholics in the U.S. (1999) accept official Church teaching against contraception, which is consistently the least popular of any doctrine surveyed (even less so among youth), being held only by the most scrupulously orthodox. By contrast, 68% accept that a Catholic must have his marriage sanctioned by the Church. The idea that religious teaching against contraceptives encourages STDs rests on the fallacy of divorcing such injunctions from the context of their full sexual ethic. I have yet to hear of any Catholics who heed Humanae Vitae yet live promiscuously (if such a thing were possible), so I must dismiss this as a straw man.
The fallacious argument above is made possible by a stubborn refusal to acknowledge the association between promiscuity and venereal disease.
This is evident in educational propaganda, where even monogamous intercourse is depicted as unsafe if lacking a condom, while promiscuous acts with a condom are safe. This completely inverts the actual degree of statistical correlation, and is therefore antithetical to the facts. How will a monogamous person magically acquire an STD? If the spouse is covertly unfaithful, any disease contracted through adultery will be passed on anyway when the couple tries to conceive. Many health educators not only neglect, but studiously avoid making a correlation between promiscuity and STD. By giving the false assurance that condoms are effective protection for a promiscuous person when disease prevalence is high, such educators are effectively prescribing the disease that it is their duty to prevent, by encouraging the behavior that is at its root.