Having Sex With Research Participants as a Research Method
Traditional anthropological fieldwork involves spending a lengthy period of time living with the community that is being studied. Many anthropologists both fall in love and/or have sex in the field,
and anthropology has long debated the ethics of the practice. Some
anthropologists (e.g., Bolton and Murray) have endorsed this as a
research method which has been called "doing fieldwork with one's body"
and they have advocated this method for the investigation of sexuality.

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It sounds like this method
It sounds like this method could also be counted as "doing research with someone else's body." Considering that these sexual partners must have sometimes been research subjects themselves. Is that wrong?
Informed Consent?
Do you still have to get it for research like this? Or is it just kind of assumed if the participant you are "studying" is naked?
Traditional anthropological
Traditional anthropological fieldwork involves spending a lengthy period of time living with the community that is being studied.