This article analyses the scientific controversies and medical issues that frame reflections on premature ejaculation. It retraces the recent history of this concept and its numerous definitions, beginning with the works of Kinsey and Masters and Johnson; and examines the evolution of these definitions in international classifications (DSM IV-R and ICD 10), which are currently being revised, and in international consensus conferences organized by academic societies in sexual medicine. This analysis reveals a lack of consensus over the question of the importance of the impact of duration of erection on the woman, and the necessity of establishing objective temporal measures or taking into account specific subjective elements in the man (the importance of control over ejaculation). The epidemiological data reflect this absence of definition consensus, added to which is the issue of the selection of criteria for the frequency of premature ejaculation or its severity as reported by the individual, the taking into account of the age of individuals concerned and the characteristics of the populations studied (general population or clinical samples). The criteria chosen for measuring frequency or severity contributes to the variation in estimates of prevalence, which ranges between 5 and 30% depending on the study. It is important, ultimately, to arrive at a consensus that will be of use not only for diagnostic purposes, but for the putting in place of treatments and the establishment of solid epidemiological data.