Hosted by the award-winning non-binary comedian Mae Martin, Fluid explores the little-known science of gender and sexual fluidity in the natural world. The film debunks dangerous pseudo-scientific myths and introduces cutting-edge research to reveal that in a very real and measurable sense, we are all gender fluid. Guided by eminent biologists Joan Roughgarden and Justin Rhodes and famed primatologist Frans de Waal, Mae discovers a hermaphroditic ginger plant, sex-changing clownfish and kobudai, and mammals––lions, hyenas and chimpanzees––that display surprisingly non-normative sexual traits. In the realm of human research, Mae meets with trans historian Jules Gill-Peterson to explore the misguided but unfortunately still influential gender studies of the 1970s and 80s. Then Mae delves into the current gender controversies, seeking out the best and most up-to-date answers from brilliant researchers including child psychologist Kristina Olson, prominent neuroscientists Gillian Einstein and Lise Eliot, and three young trans/non binary scientists––Daniel Pfau, Elle Lett and Simone Sun––who take on the challenges of gender research from a gender non-conforming perspective. Mae also meets a group of trans youth who candidly reveal their difficult life experiences and hopes for a future that is more inclusive and accepting. Along the way, Mae shares reflections through relevant and hilarious material from their live standup performances.