Professional standards in medicine and psychology treat concurrent sexual relationships with patients as violations of fiduciary trust, and they sometimes rule out sexual relationships even after a clinical relationship is over. These standards also rule out sex with research subjects who are also patients, but what about nonclinical relationships where there are not always parallels to the standards of clinical medicine? One way to treat sex in nonclinical research relationships is to treat it as sex is treated elsewhere among adults, (...) as a matter of individual choice and responsibility. Alternately, one could ask oversight bodies to draw lines between research that can safely accommodate sexual relationships and research that cannot. One could even ask researchers to avoid all concurrent sexual relationships with their research participants, as happens in clinical medicine. Each of these options has drawbacks that undermine its value as a definitive solution. The deficiencies of these options highlight the need for a professional code of conduct for nonclinical researchers. (shrink)