Problem Based Learning (PBL) makes use of real-life scenarios to stimulate students' prior knowledge and to provide a meaningful context that is also related to the student's future professional work. In this article, Paternity testing is presented using a PBL approach that involves a combination of classroom, laboratory, and out-of-class activities: in relation to a fictitious newborn found on the Campus, students design a PCR based protocol to determine their own genotype for two markers. Pooled class genotypes serve to calculate allelic frequencies and to assess Hardy-Weinberg equilibrium. Individual results are also evaluated for possible paternity. The goals of the activity and how each step in the process relates to learning outcomes are presented. Classroom discussions, group discussions, tutorial sessions, wiki sites, laboratory activities, and individual reports sum up the situations, in which the students' process of learning and learning outcomes can be evaluated. (Contains 2 figures and 1 table.)