Eric Gaillard / Reuters

Today Alabama enacted a law that will require, as a condition of parole, that some convicted child sex offenders undergo “chemical castration.”

The new law will mean that those who abused children under the age of 13 will be injected with hormone-blocking drugs before leaving prison. The medication will have to be administered until a judge, not a doctor, deemed it no longer necessary.

A similar bill was proposed last year in Oklahoma but met strong opposition. The former Soviet republic of Moldova also passed a law mandating chemical castration for child sex offenders, in 2012. It was repealed the following year on grounds that it was a “violation of fundamental human rights.”

Unlike castrating a bull, chemical castration does not involve removing a person’s testicles—though the Alabama bill’s sponsor, Representative Steve Hurst, initially advocated the surgical approach. Instead, the procedure uses various drugs to render the testicles irrelevant. In most cases, medication triggers the pituitary gland to reduce testosterone to prepubescent levels. During debate of the bill, Hurst said that if chemical castration, which has a stated goal of decreasing libido to prevent future crimes, “will help one or two children, and decrease that urge to the point that person does not harm that child, it’s worth it.”

If we could put ethical considerations about nonconsensual medical treatment aside, it still wouldn’t be clear whether this approach will have the desired effect on recidivism. Most research in the area puts sexual desire low on the list of reasons people assault children. The best predictor of sexual assault is not libido, research has shown, but “an early and persistent general propensity to act in an antisocial manner during childhood and adolescence.”

The physiological effects of androgen blockers are well established, because the drugs used in chemical castration are also commonly used in people with cancer, especially of the prostate, where testosterone can help tumors grow. In addition to lowering libido and causing sexual dysfunction, the sudden removal of androgenic hormones has been known to impair performance on visual-motor tasks and cause declines in bone density, increased rates of fractures, and depressive symptoms.

It has been well demonstrated that surgical castration, which has been practiced in various places for millennia, makes sex offenders either unwilling or simply unable to commit future offenses. The evidence on chemical castration is much less clear. In the same way that removing the hands of a bread thief could theoretically help prevent future crimes, rendering a person’s genitals less virile makes certain acts less feasible. But unlike other therapeutic approaches, chemical castration (or surgical castration, for that matter) does not address the antisocial instincts that often underlie such crimes.

Some ethicists argue that child offenders are diseased, and it is only humane to treat them—even sometimes without consent. This is predicated on the basic idea that assault is a result of an imbalance of hormones, whereby too much testosterone leads to rape. On the whole, however, sex offenders do not have higher levels of testosterone than the average male. A recent meta-analysis of research found “no evidence to suggest there is anything chemically wrong with sexual offenders.”

Assault is not a typical outlet for those who have strong libidos or think often about sex. The desire to take another person by force has long been known to be primarily about power and dominance. If chemical castration is indeed effective, the meta-analysis notes, “it is not because it is treating an abnormal medical condition, but rather because it is inhibiting sexual functioning in the same way it would for most humans.”

In psychiatry, there are some accepted uses for androgen-blocking medications. As the Johns Hopkins psychiatrist Fred Berlin has noted, in these cases drugs are used for “diminishing the intensity of the eroticized urges that energize unacceptable para-philic behaviors”—in other words, when a person is concerned about acting on urges they know to be wrong or illegal, and so seeks preventive help. Other people seek help when an all-consuming libido becomes a problem in daily life.

Research has found small reductions of recidivism among convicted sex offenders when they request chemical castration in conjunction with other therapeutic measures. Small studies have found that recidivism decreased when offenders received antidepressant medications, not anti-testosterone medications.

These findings largely leave the question of whether the technique should be used to the realms of ethics and legality, not medicine. Some legal scholars believe mandatory chemical castration violates the Eighth Amendment, which bans cruel and unusual punishment. The University of Florida law professor John Stinneford has called the practice “maiming” and “impermissibly cruel.” (Hurst, the Alabama bill’s sponsor, did not respond to a request for comment.)

Even when chemical castration is voluntary—which other legal scholars argue can never be the case, due to the coercive subtext of lessening prison sentencing for seeking the procedure—treatment of “hypersexuality” has a loaded history in the United States and elsewhere. The medical establishment and government have long erred on the side of narrowly defining normalcy and punishing “deviancy,” as they have with homosexuality, which was removed from psychiatry’s Diagnostic and Statistical Manual of Mental Disorders only in 1973.

This change came after researchers began documenting in mainstream journals the wide variations in human sexuality. The range of what was “normal” began to separate from morality and expand to show that the idea of what constitutes sexuality is vast and complex. Today, the psychiatric establishment still uses a diagnosis of hypersexual disorder, but the concept has shifted from a more rigid imposition of norms to an idea about how a person relates to sex. There is no cutoff for what is too much sexuality. Some people have sex multiple times a day; others rarely have sex. Hypersexual disorder is currently defined only insofar as it causes distress: When you lose your job because you need to keep having sex, or when your relationship falls apart because you lose all interest in sex, you may have reason to seek care.

If there is a role for the medical community in preventing assault, it is to help equip willing patients relate to people in healthy ways—to treat whatever psychological element precludes healthful, pro-social behavior. If such people find themselves in court, they could be offered the same option. This has been the suggestion of some physicians in South Korea, for example, who argue that chemical castration can be an effective tool for offenders who want and consent to the treatment “within the context of simultaneous comprehensive psychotherapeutic treatment.” Denmark has implemented options for “sexological treatment” of some sex offenders that includes therapy and androgen-blocking medications.

In every case, though, the suggestion is that this would be consensual, voluntary care. It would heed the words of Berlin, the Johns Hopkins psychiatrist, who writes that chemical castration cannot “effectively assist” a person “who lacks a sense of conscience and moral responsibility by somehow instilling appropriate values.”

To have the state impose mandatory standards of behavior toward other people is one thing; to forcibly regulate someone’s internal sex drive is another.

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