Islam encourages men and women to try their best to apply the teachings of Islam in their daily lives and to avoid all measures that constitute a violation to the teachings of Islam. With this in mind, all ways of achieving permanent sterility are forbidden.
Dr. `Abdul-Wahhab ibn Nasir Al-Tariri, former professor of Shari`ah at Imam Muhammad Ibn Saud University, Saudi Arabia, states the following: Sterilization of both men and women is prohibited in Islam. The Prophet (peace and blessings be upon him) expressly forbid castration.
Abdullah ibn `Abbas (may Allah be pleased with him) narrated: “We were on a campaign with the Prophet (peace and blessings be upon him) and were destitute, so we asked if we could have ourselves castrated. The Prophet (peace and blessings be upon him) prohibited this. Then he permitted us to get married with a dowry of a single garment” (Al-Bukhari).
All other means of achieving permanent sterility are equally forbidden. The only exception to this is in cases of medical necessity. If something is prohibited for Muslims, it is also prohibited for Muslims to provide it for non-Muslims, unless there is a specific proof indicating otherwise. Therefore, a Muslim cannot sterilize a non-Muslim except out of medical necessity.
We as Muslims are obliged to call non-Muslims to what is right, not assist them in doing wrong. Imagine a case where a non-Muslim woman has this operation done and then later on accepts Islam. After becoming Muslim, she wishes to marry a Muslim man and have children, but she cannot do so because she failed to have the operation successfully reversed.
It is worth mentioning that the scholars prohibit sterilization even for animals, except in cases where there is a real benefit from doing so.
Imam Al-Qurtubi stated, “It is prohibited to castrate an animal except for a tangible benefit, like improving the quality of meat or preventing harm.”
An-Nawawi wrote, “It is categorically forbidden to castrate animals that cannot be used for food. As for animals that can be used for food, it is permissible to castrate the juveniles but not the adults.”