Thank you very much for pointing out that "jouissance" is also an English word. I completely agree, and in most cases I would suggest that it is preferable to use it as such.
However, I think it probably should not be used here, due to the nature of the field. Sexology is interdisciplinary, but it often seems to tend to follow a more medical paradigm. For example, see:
http://ur1.ca/bvq6bThe term "jouissance" is not to my knowledge used in medical English, except in the specialty of psychoanalysis (insofar as psychoanalysis is a specialty of medicine - that's both a theoretical issue and the kind of question that gets different answers depending on who is asked...).
In any case, a PubMed search for articles in English containing "jouissance" gives only six results, all of which are from psychoanalytic journals. See:
http://ur1.ca/bvpzmSo I'd say that if the article has many medical and biological terms and explanations, then it would be better not to use "jouissance." It could also be useful to consider where the article is to be published or presented and to look at the bibliography to see if the references are more socio-cultural or medico-biological in nature.