This case is based on a true story of a woman whose children were almost taken from her because her DNA profile indicated that she was not the mother of her children. The interrupted case study follows the woman, her lawyer, and a research biologist as they try to determine why her DNA profile does not match her children’s profiles. In the course of learning about this very unusual case, students review the normal process of reproduction and genetic transmission in humans, form and evaluate hypotheses about the case, and are challenged to think about the possible implications of abnormal transmission of genes.