Scientists have developed a model that will enable them to investigate, for the first time, how human testes develop in baby boys while they are in the womb. Until now it has been impossible to study testicular development during pregnancy in humans and this discovery will enable researchers to understand the processes that can lead to the onset of testicular germ cell cancer (TGCC) in young adult life, and how factors, such as common environmental chemicals, might play a role. The research is published in Human Reproduction journal on Wednesday 4 August.