Two major hypotheses have been put forward to describe the criminal activity of sexual offenders in adulthood. The first hypothesis states that sexual offenders are specialists who tend to repeat sexual crimes. The second hypothesis describes sexual offenders as generalists who do not restrict themselves to one particular type of crime. The current state of knowledge provides empirical support for both the specialization and the generality hypothesis. The presence of both generality and specialization in the offending behavior of sexual offenders is not as contradictory as it may first appear. However, methodological problems limit the possibility of drawing firm conclusions. Indeed, the specialization hypothesis is based on just one parameter of criminal activity, that is, recidivism, which only takes into account two consecutive crimes. The generality hypothesis is focused mainly on two criminal activity parameters, participation and variety, which do not take into account the dynamic nature of criminal activity over time. Developmental criminology provides a new paradigm to explore the issue of generality and specialization in the offending behavior of sexual offenders.