This article interrogates the scientific conference as a means by which the organizers of the World League for Sexual Reform's 1929 conference attempted to marshal the ‘scientific spirit’ in order to present progressive sexual reform as a rational and scientifically informed undertaking. The conference was carefully curated to make the sex reform movement (and the assorted characters that gathered under its banner) look serious, legitimate and, most importantly, scientific. The conference was also an attempt by organizer Norman Haire to exert (...) control over the strategy of sexology, an enterprise that put him at odds with other prominent sexologists of the time. Crucially, Haire understood sexology as inherently intellectually interdisciplinary, but was strategically convinced that the only sound rubric through which to promote and gain acceptance for the movement was through medical science. This central debate, about how best to define the contested concept of sexology, continues among historians today. By examining how the 1929 conference organizers wrestled to define their sex-reforming remit and how they curated the conference to that end, this paper will offer a window onto the mechanisms via which adherents of intellectual communities contend with heterogeneity, how we judge forms of knowledge and, ultimately, what constitutes science. (shrink)