"Chemical castration" is a popular term for what doctors call "anti-libidinal" treatment. It means reducing male testosterone by administering a drug similar to the female hormone progesterone through injections or pills.

"There are indications that it works, but there is no concrete evidence to prove how effective it is," Jürgen Müller, a Göttingen-based neurologist, and forensic psychiatrist, told DW.

To date, no international study has been conducted that could effectively evaluate the success of this treatment. 

But several countries in Europe, including Germany, offer castration to potential and convicted sexual offenders — as one form of treatment, not as a punishment, and only on a voluntary basis.

A model for Pakistan?

Pakistan is currently debating whether it should introduce "chemical castration" as a punishment for sexual abuse. 

Life imprisonment and the death penalty are the current punishment options for rapists and pedophile offenders under Pakistan's criminal code.

But the country is considering additional measures following nationwide outrage in response to a growing number of rape cases.

In 2018, 7-year-old Zainab was raped and murdered in the district of Kasur near the provincial capital of Lahore. In the wake of this incident, violent protests erupted in Kasur, and people all over the country took to the streets demanding justice.

During the DNA testing of the suspect, it was found that he was responsible for at least five other rapes. He was hanged for his crimes the same year.

In 2020, the nation was once again enraged when a woman was gang-raped on a motorway near Lahore in front of her two young children. The case is still being tried in court.

Prime Minister Imran Khan suggested public hangings of rapists and pedophiles. But he stressed that international pressure was holding him back: Pakistan's trade status with the European Union could be threatened, he said.

"What my opinion is is that we should do 'chemical castration'; we need new laws that leave these people incapable of any sexual acts," Khan then suggested, and an ordinance was proposed that would add anti-libidinal treatment to the penal code.

Does 'chemical castration' prevent rape?

Chemical castration has been found to be effective in reducing sex drive and the seminal fluid in a male. But this does not prevent sexual violence or aggressive behavior.

Even reducing the testosterone level to zero does not eliminate chances of reoffending. "One doesn't need to have an erection to be able to molest a child or rape a person," explains sociologist Andrej König from Dortmund University. Even if the men cannot penetrate, they can still show aggressive and problematic behavior.

Serious side effects and ethical aspects

"Chemical castration" is not a quick procedure — the drugs are prescribed for a certain period or indefinitely. They are likely to trigger heavy side effects, including breast growth, depression and the risk of osteoporosis, among other things.

In Germany and other European countries, castration is based firmly on consent. It is administered to sex offenders on a voluntary basis. 

"Some perpetrators feel a certain amount of guilt and disgust at their actions; for them, this (chemical treatment) is a kind of atonement," forensic psychiatrist Callum Ross at Broadmoor Hospital in the UK told DW.

"Drug treatment is always embedded in behavioral therapy or psychotherapy," JürgenMüller explains. Drive-attenuating chemical treatment alone is not sufficient, he adds — this is only one of the many therapeutic approaches to deal with sexual offenders.

To employ drug treatment with a lot of side effects as a punishment is a "very, very problematic" idea, he warns, calling it questionable "from a medico-ethical perspective."

Whether offenders opt for castration in a genuine bid to change is difficult to gauge, cautions sociologist König. Individuals cannot be forced to undergo it, but if they are offered some freedom, they are more likely to "volunteer," he added.

In the UK and Germany, for example, prisoners have admitted to opting for the treatment if they felt it might reduce their prison time or help secure them early parole.

However: "Chemical castration should not be a substitute for reforming the prison system," warns Thomas Douglas, a professor of applied philosophy at the Oxford Uehiro Centre for Applied Ethics. He advocates for rehabilitation programs for offenders and their reintegration into society.

Chemical vs surgical castration

Europe has employed both surgical and "chemical castration" in the past and present — but only for certain aggressive, violent sexual offenders.

The Czech Republic is the only country to currently take the surgical route, where the gonads are removed through an incision in the body.

"This is the only reliable way to treat the most aggressive of the offenders," Czech sociologist Katerina Liskova of Masaryk University told DW. The number of sex offenders opting for surgical castration is small, Liskova stressed: "It is a tiny number of men, and they opt for it voluntarily," she said.

She pointed to studies in the Czech Republic, where only four in 100 sex offenders who had been surgically castrated later offended again.

Until 2012, Germany, too, offered sexual offenders the option of surgical castration. But the practice was abolished in response to criticism from the Council of Europe's Committee for the Prevention of Torture and Inhuman or Degrading Punishment. 

At present, Germany offers "chemical castration" as an option in forensic psychiatric settings — for sex offenders who are mentally ill and dangerous and are housed in high-security hospitals.

About 25% of patients in forensic hospitals take medicine for "chemical castration" only on a voluntary basis, according to sociologist Andrej König. Germany has no statistical evidence proving that the treatment definitely reduces the chance of reoffending.

"I have never met a patient who said they took the medicine and now have no sexual fantasies or urges of masturbation," he said. "It doesn't change their fantasies either. If a pedophile takes part in a 'chemical castration' program, his fantasies won't change. They may not be as frequent, but they still exist," he told DW.

Structural reform needed in Pakistan

Pakistan is considering the introduction of "chemical castration" as a mandatory rather than voluntary measure as part of the sentence for sex offenders.

European experts are skeptical.

Introducing draconian measures can be a vote-winner, says forensic psychiatrist Callum Ross. But he urges an understanding that "chemical castration" is a form of treatment, not of punishment. 

"Chemical castration has not made society safer; still, it is propagated by conservative or right-wing parties as a solution for sex offenders," says criminologist Dirk Baier of the ZHAW Institute of Delinquency at Zurich University in Switzerland. "It is a measure that enjoys high approval rates in some countries, where it contributes to a higher sense of security, even though there is no evidence for this."

In Pakistan, the women and children's rights movement "Aurat March Lahore" is critical of the idea. The movement demands a reform that "overturns patriarchal structures" rather than "short-term measures" such as a legal provision for "chemical castration."