As already mentioned, it is an ethical principle that the researcher should not inflict on volunteers anything that the researcher would not be willing to do to him- or herself, but the researcher is not always a suitable, or even possible, subject for the experiment. For instance, the researcher may be the wrong gender if the research is into hormone treatment for women, or may be too old, or too young. The ethical question for the researchers is would they agree to the experiment if they were in the same position as the volunteers?