With this change, however, there are ethical concerns which lack adequate attention, and which must be addressed before eugenic policies can be properly implemented in the future. Sterilized individuals, for example, could volunteer for the procedure, albeit under incentive or duress, or at least voice their opinion. The unborn fetus on which these new eugenic procedures are performed cannot speak out, as the fetus lacks the voice to consent or to express his or her opinion. Philosophers disagree about the proper framework for reasoning about such actions, which change the very identity and existence of future persons.