Designer crossbreed dogs, such as Cavapoos, Cockapoos, and Labradoodles, have surged in popularity across the UK, with many prospective owners drawn to them by the perception that crossbreeds are healthier than their purebred ancestors. This belief is based on the concept of 'hybrid vigor,' or heterosis, which suggests that offspring from the intentional crossing of distinct breeds should exhibit improved health and vitality. However, scientific evidence supporting the health benefits of designer crossbreeds is limited, prompting a need for more robust research to inform potential dog owners.