Sir Hirini Moko Mead’s Five Tests framework helps identify a te ao Māori response to contemporary challenges. One such issue that Mead confronted, more than two decades ago, was genetic modification. We applied Mead’s precedent test to a genetic technology under development in Aotearoa New Zealand called single-sex offspring selection (SSOS). Single-sex offspring selection aims to control rat populations that harm native species either by producing primarily male litters or, by rendering females infertile, through a gene drive. We sought precedents for sex selection of offspring and causing infertility in Māori tradition by surveying whakataukī and 19th- and 20th-century written secondary sources containing mātauranga Māori. The search revealed examples of parents choosing the sex of their future children and of causing infertility in women and in kurī, indicating that the underlying concepts of SSOS’s control methods are not entirely new to te ao Māori, even if the delivery mechanism is. The precedent test invites us to learn about and reconnect with ancestral practice, helps to conceptualise and understand the issue at hand, and helps form a Māori response to complex novel technologies.