Did you know that the Irish government is putting a bill through parliament in which it will allow courts decide to sterilize people who are of diminished mental capacity? The Act, the Assisted Decision-Making (Capacity) Bill 2013, gives the High Court the jurisdiction with regard to non-therapeutic sterilization on "a relevant person who lacks capacity" (See part 1, section 4, article 2).
Non-therapeutic sterilization is sterilization not required to treat a serious condition, but rendering a physically healthy person sterile. In essence, it is a eugenic/contraceptive act.
As far as I am aware, and I am open to correction here, until this Act is passed, I'm not sure if Ireland permits involuntary non-therapeutic sterilization on the mentally ill or those of diminished capacity.