The energy required to grow, birth and raise young is intense, so it's only fair that the female body has some tricks to make sure reproducing is worth it. From cryptic choice to immune system sperm blockers, the female reproductive system can be a literal maze for those seeking to gain access to her eggs. In the battle of the sexes, this is females fight back. Sex is Weird is a new series of What the Duck?! with Dr Ann Jones following the sexual evolution of the animal kingdom. Please note that this program contains adult themes and explicit language. Parental guidance is recommended. Featuring: Professor Sarah Robertson, University of Adelaide.   Dr Diane Kelly, Assistant Professor, University of Massachusetts, Amherst. Associate Professor Patricia Brennan, Mount Holyoke College, Massachusetts, US. Emeritus Professor Susan Suarez, Cornell University, New York. Professor Mariana Wolfner, Cornell University, New York.   Production: Ann Jones, Presenter / Producer. Petria Ladgrove, Producer. Additional mastering: Isabella Tropiano.   This episode of What the Duck?! was produced on the land of the Wadawarrung and the Kaurna people.