[2] Chemical castration is generally reversible when treatment is discontinued,[3] although permanent effects in body chemistry can sometimes be seen, as in the case of bone density loss increasing with length of use of depot medroxyprogesterone acetate (DMPA).
In men, chemical castration reduces sex drive and the capacity for sexual arousal, side effects of some drugs may include depression, suicidal ideation, hot flashes, anemia, infertility, increase in body fat and higher risks of cardiovascular diseases and osteoporosis.
In women, chemical castration acts by decreasing testosterone levels in order to lower their sex drive, side effects include the deflation of breast glands, expansion of the size of the nipple and shrinking of bone mass.
[18] In 1981, in an experiment by Pierre Gagné, 48 males with long-standing histories of sexually deviant behaviour were given medroxyprogesterone acetate for as long as 12 months.
The research recorded a continuation of this improved behaviour after the administration of the drug had ended, with no evidence of adverse side effects, and so recommended medroxyprogesterone acetate along with counselling as a successful method of treatment for serial sex offenders.
[6] Some criminologists argue that the appearance of a lower recidivism rate in male sex offenders who take chemical castration treatment than in those who do not can be explained by factors other than biological effects of the medication.
These scientists therefore argue that the biological (as opposed to sociological) effect of reduced testosterone is to make it more difficult and not easier to use masturbation without pornography or other socially acceptable substitutes to manage remaining sex drive in a former offender, and that many community persons (both male and female) find that a lower initial arousal makes it more difficult to orgasm by masturbation without pornography or with non-preferred stimulation.
[31] In March 2010, Guillermo Fontana of CNN reported that officials in Mendoza, a province in Argentina, approved the use of voluntary chemical castration for rapists, in return for reduced sentences.
[41] Law professor John Stinneford has argued that chemical castration is a cruel and unusual punishment because it exerts control over the mind of sex offenders to render them incapable of sexual desire and subjects them to the physical changes caused by the hormones used.
[17] In the case of voluntary statutes, the ability to give informed consent is also an issue; in 1984, the U.S. state of Michigan's court of appeals held that mandating chemical castration as a condition of probation was unlawful on the grounds that the drug medroxyprogesterone acetate had not yet gained acceptance as being safe and reliable and also due to the difficulty of obtaining informed consent under these circumstances.
"[54] The Anti-Rape Ordinance 2020, approved by President Arif Alvi in December 2020,[55] allows for chemical castration of rapists without the consent of the offender.
[57] In July 2011, South Korea enacted a law allowing judges the power to sentence sex offenders who have attacked children under the age of 16 to chemical castration.
On May 23, 2012, a serial sex offender legally called Park in the court case was ordered by the committee to undergo this treatment after his most recent attempted offense.
Legislation allowing chemical castration exists in France, the United Kingdom, Poland, Russia, North Macedonia, Belgium and Turkey.
[17] On June 5, 2012, Estonia passed a law that allows voluntary chemical castration as a part of complex treatment for less serious sex offenders as an alternative of imprisonment.
[63] In October and November 2013, North Macedonia authorities were working on developing a legal framework and standard procedure for implementation of chemical castration that would be used for convicted child molesters.
[65] This law came into effect on June 9, 2010; therefore in Poland "anyone guilty of raping a child under the age of 15 can now be forced to submit to chemical and psychological therapy to reduce sex drive at the end of a prison term".
[68] In October 2011, the Russian parliament approved a law that allows a court-requested forensic psychiatrist to prescribe the chemical castration of convicted sex offenders who have harmed children under the age of 14.
[71] In 2009 British Prime Minister Gordon Brown issued a public apology for the "appalling" treatment of Turing after an online petition gained 30,000 signatures and international recognition.
[73] On April 30, 2010, a 30-year-old man in the United Kingdom found guilty of attempting to murder a 60-year-old woman in order to abduct and rape her two granddaughters (aged eight and two) agreed to undergo chemical castration as part of the terms of his sentence.
[74] In 2010, a 58-year-old repeat child sex offender who had been subject to chemical castration was accused of inappropriately touching and kissing a seven-year-old young girl.
[77][78] In 2020 a man in Canada who was receiving antiandrogen drug treatment for colon cancer murdered his doctor over the belief that they were chemically castrating him due to his race.