I am a doctor in a western country. Part of my job is to do female sterilization for their patients. What is the Islamic opinion on this?

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. It is unlawful for any woman to block the way to conception unless there is a real threat to her life and she cannot find another way to protect her life. This is an issue that should be decided through a testimony of a trusted physician. If any woman whose condition is as described above and there is no female physician for you to refer her, you can then perform the sterilization for her, but revealing her nakedness only to the extent which is necessary. You should also not be in seclusion with her. Allah knows best.