Kaduna Lawmakers have approved surgical castration as a penalty for the rape of children under the age of 14.
The bill however awaits the assent of the Nasir Ahmad el-Rufai before it becomes law in the state.
El-Rufai had previously endorsed castration as a means to prevent rapists from re-offending.
In Nigeria, the federal law provides between 14 years and life imprisonment as punishment, but state legislators can set different sentencing rules.
Stigma often prevents victims from reporting incidents of rape in Nigeria and the number of successful prosecutions is low.
Nigerian governors in June declared a state of emergency over rape and violence against women and children.
Since 2015, when a new law was introduced, about 40 rape suspects have been charged, according to the National Agency for the Prohibition of Trafficking in Persons (NAPTIP), which has a sex offenders list on its website.
The new law broadened the scope under which sexual offences can be penalised in Nigeria and removed the time limit of two months during which rape cases had to be tried before they became ineligible to be heard in a court.
The head of NAPTIP, Julie Okah-Donli in an interview with the BBC said that as the burden of proof is on the prosecution, proving rape cases is “quite tedious and technical”.
Many Nigerians for a while have called for surgical castration as punishment for convicted rapists the spate of occurrence surged during the recent coronavirus lockdown.
There was widespread outrage in July following the murder of a 22-year-old university student who her family say was brutally raped and bludgeoned to death.
Many Nigerians called for stiffer laws, such as the death penalty.
Kaduna lawmaker Shehu Yunusa said, “We feel that the new law will go a long way to curbing rising cases of rapes in our state.
“If the Kaduna governor signs [this] into law, the next rapist caught in Kaduna might become the first person to be castrated under this new law.”
Gender activist Dorothy Njemanze – a former victim herself – welcomed the bill and said she would like to see it adopted in other Nigerian states.
“In retrospect, if everyone that raped me was put through that [surgical castration] other people that they might have also raped would have been spared the calamity,” she said.
Surgical castration is not widely practiced in the world and is considered controversial in the few places where it is still used.
It is not in the guidelines drawn up by the International Association for the Treatment of Sexual Offenders (IATSO) and critics argue that the physical effects are irreversible and may have serious physical and mental consequences.