Why do humans have precisely five fingers and toes? How does a bone know to stop growing when it reaches the appropriate length? What controls our gender? While the human genome successfully encodes the information required to produce a “normal” human being, genetic variation dictates the subtle and not so subtle differences that make us each a unique individual. “Mutant” humans throughout history have provided insights into how genetics underlie development by showing us what can happen when the delicate balance of genes and their proper expression is perturbed. This course will focus (a little bit) on the history and (a lot) on the science behind some of the more pronounced human “mutant” conditions, including conjoined twinning, dwarfism and giantism, and progeria (rapid aging), to name a few. Students will also read and discuss recent scientific developments such as personalized medicine, preimplantation genetic diagnosis, and stem cells.