Dr. Sara Good is part of a research team who are investigating the genetic pathways involved in sex determination and differentiation of one of the world’s most fascinating creatures. Sometimes referred to as the ‘vampire fish,’ lamprey have captivated researchers because of their unusual biology and ancient lineage. Good’s research into these unique vertebrates is not only providing new insights into the evolutionary development of sex determination mechanisms across different species but has the potential to play a pivotal role in the future of the Great Lakes fisheries by assisting in the control of lamprey populations. On this episode the research question is: what can lampreys tell us about the complexity of sexual determination in nature?