1. Does sadomasochism have a biological purpose, i.e. does it increase reproductive success under at least some circumstances, and if so, how?
[ Sadomasochism is so common, that it is very likely to have some purpose, otherwise it would have long since evolved away. ]
2. Why is the occurrence of sadomasochism strongly correlated with clothing fetishes involving leather, rubber, PVC and any other shiny fabric?
[ This is almost the hardest question for any theory that claims to explain these phenomena. Most authors put it in the too hard basket, or even just ignore it. ]
3. What is the full range of sexual preferences and activities associated with sadomasochism?
[ An objective physiological criterion for S&M is needed to answer this question. There may turn out to be a few surprises. ]
4. Is there one basic phenomenon that underlies all those preferences and activities?
[ Probably yes. ]
5. Is there some part of the brain specifically devoted to sadomasochism? Is there some specific neurotransmitter involved?
[ First part: very probably, if sadomasochism has a specific function. Second part: maybe. ]
6. What effects do psychoactive drugs have on sadomasochism, and can they be distinguished from effects on overall sex drive?
[ Note: Do not attempt to answer this question by experimenting outside a proper laboratory that is equipped and licenced to perform such experiments. This is most revelant if the answer to the second part of question 5 is yes, as psychoactive drugs generally act on neurotransmitter systems (rather than on specific locations). ]
7. Is there a group of people who are sadomasochists distinct from those people who are not sadomasochists, or is it variation along a continuum?
[ My guess: yes. Further question: is there anything unusual about those at the extreme vanilla end of the spectrum? ]
8. Are there any genes that determine sadomasochism?
[ Possibly, given the extreme variation that is observed. ]
9. What is the concordance rate for identical twins?
[ This is the standard way to answer the previous question. It ignores all difficulties as to whether the genetic effect is a complex one involving many genes or a simple one involving one or just a few genes. ]
10. Are there environmental causes or triggers for sadomasochism? If so, do they relate to the biological purpose (if any) that sadomasochism has?
[ Probably yes. One would expect sadomasochism to be triggered by those circumstances in which the purpose of it was more relevant, for example when opportunities for sexual satisfaction are difficult or infrequent. ]
11. Is anything like sadomasochism observed in non-human animals?
[ Probably not. ]