This paper presents the results of a three-stage Delphi study examining the current level of consensus among 24 professionals in the United Kingdom regarding definitions of and distinctions between normal, inappropriate and sexually abusive behaviours in children under 10 years, as well as factors influencing their views. Although firm conclusions cannot be drawn, findings indicate high consensus that children should not be called "sex offenders/abusers" and that behaviours which use force or resemble adult sexual behaviours are concerning. Watching pornography was rated similarly. A high consensus regarding acceptable sexual behaviours was obtained on a couple of items. Divergent views existed regarding various sexual behaviours, and no consensus was reached on what terminology should be used. Professionals agreed that their views were influenced to some extent by professional and personal experiences, and values. Implications for clinical work and research are discussed. (Contains 1 table.)