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Why is chemical castration being used on offenders in some countries?

Written by Dr Jonathan Pugh
This article was originally published on The Conversation
The answer for some. Shutterstock

Following a horrific act of sexual violence against a 14-year-old girl, the president of Indonesia, Joko Widodo, recently signed a decree into law, which, among other things, authorised the death penalty for convicted child sex offenders, and also the use of chemical castration of such offenders.

The main justification cited by Widodo was that castration would act as a deterrent. But how do such interventions fit in the criminal justice system? Are they likely to be successful?

The Indonesian decree is more unusual because it authorises judges to impose chemical castration as a non-optional part of an offender’s punishment, rather than offering it as an alternative to imprisonment. Yet even in this regard the decree is not unprecedented; other jurisdictions (including, among others, South Korea, Poland, Estonia, and the US states of California and Florida) have authorised the mandatory use of chemical castration for certain convicted sex offenders.


Chemical castration involves the administration of drugs that reduce the recipient’s libido and, it is hoped, their sexual activity. Unlike physical castration, the effects of chemical castration on the recipient’s sex drive are reversible. However, opponents of chemical castration often point out that the long-term use of some of these drugs is associated with permanent adverse side-effects, including an increased risk of osteoporosis, cardiovascular disease, and impaired glucose and lipid metabolism.

It is commonly claimed that one of the primary aims of punishment is to rehabilitate offenders so that they will not reoffend. Traditional penal methods (such as imprisonment), and psychological therapies (such as cognitive behavioural therapy), have not been particularly effective at preventing reoffending among sex offenders.

While chemical castration is championed as an effective tool for achieving this, the World Federation of Societies of Biological Psychiatry (an international organisation representing over 4,500 professional psychiatrists) points out that many of the studies that support this claim provide only limited evidence. This is because many of these studies lack adequate controls, partly for ethical reasons. Doctors in Indonesia have also refused to take part in chemical castrations.


Widodo sought to justify the decree by pointing out that “sexual violence against children has increased significantly” in Indonesia, and that the decree will “provide space for the judge to decide severe punishments as a deterrent effect on perpetrators”.

“Deterrence” here is ambiguous: it might refer to the effect that chemical castration (and the death penalty) may have on deterring the recipient from reoffending; or more generally to the deterrent effect on others who may offend. Deterrence of the general sort, such as rehabilitation, is often understood as a justifiable aim of punishment that stresses the importance of it leading to good consequences for society. However, the justification for chemical castration as a general deterrent is arguably on weaker ground than the justification of it as a rehabilitative measure.

When it comes to rehabilitation, there are arguably some grounds for authorising chemical castration rather than some other form of punishment, in so far as the available empirical evidence provides at least some (arguably limited) justification for the claim that chemical castration has a direct effect on whether or not the recipient will reoffend.

In an obvious sense, the death penalty will also have an anti-recidivist effect – you’re hardly going to reoffend if you’re executed. So we might ask, even without considering the lack of empirical evidence regarding whether either chemical castration or the death penalty are effective general deterrents, why chemical castration is necessary for general deterrence, when a more severe punishment is already a possibility.


One explanation for why Indonesia legalised chemical castration in addition to the death penalty might be found in retributive approaches to the justification of punishment. These stress the importance of offenders receiving their “just deserts”. Some claim that a punishment must not only impose a burden proportionate to the harm the offender caused but must also, in a symbolic sense, fit the crime. While the death penalty might be more severe than the use of chemical castration, the latter might be deemed a more fitting form for sexual offenders.

Non-optional if decreed. Shutterstock

However, this justification of chemical castration, and the argument from general deterrence, both turn on a contentious issue that lies at the heart of a deep moral question regarding sexual offenders.

The theory of retribution holds that criminal offenders deserve to be punished. This relies on the assumption that offenders are morally responsible for their crimes. In a similar vein, the claim that increasingly severe punishments will act as an effective general deterrent assumes that they will influence an individual’s decision about whether to commit acts of sexual violence.

However, these assumptions lie in tension with the thought that some sexual offenders suffer from a mental disorder that causes them to act on the basis of compulsive desires. These desires may not be sensitive to rational disincentives, and some might argue that individuals are not morally responsible for acts motivated by compulsive desires.

We can’t settle these complex issues here. However, the rehabilitative justification of chemical castration is a stronger justification for these punishments. If Indonesia has legalised chemical castration in order to reduce offending, this may be plausible on the grounds of individual rehabilitation, but we need more evidence to establish that it will be effective as a general deterrent, and more philosophy to establish whether it should be used for retribution.

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