The pursuit of mating opportunities, even at the best of times, can pose a significant challenge to sexually reproducing organisms. Charles Darwin in the Origin of Species described it as a ‘sexual struggle’ arising from intense competition among individuals for the opportunity to mate. This struggle can be so powerful that it can shape the course of evolution itself – a process known as sexual selection. In most animals, reproduction is finely attuned to the environment. So, what happens when environmental conditions are disturbed due to anthropogenic activities? One particularly insidious form of anthropogenic disturbance is contamination of the environment by a myriad of human and veterinary pharmaceuticals that can affect the behaviour, morphology and physiology of non-target organisms. In this talk, I will consider the pivotal role that reproductive behaviour plays in determining the fate of individuals, species and populations under human-induced environmental change, and discuss recent research investigating the ecological and evolutionary impacts of pharmaceutical contaminants on reproduction and mechanisms of sexual selection in fish.