To involve students in thinking about the problem of AIDS (which is important in the view of nondecreasing infection rates), we established a practical lab using a simplified adaptation of Thomas's (2004) method to determine the polymorphism of HIV co-receptor CCR5 from students' own epithelial cells. CCR5 is a receptor involved in inflammatory processes, which has been misused by some pathogens, including HIV, to enter host cells. As a result, a defective allele "CCR5-?32" has been enriched in some populations. The interesting story and hands-on work with their own tissue absorbed students in this 2-hour practical.