The human body is a machine whose many parts – from the microscopic details of our cells to our limbs, eyes, liver and brain – have been assembled in fits and starts over the four billion years of our ...

If we look across the whole of the mammal branch of the tree of life, we find there are many groups of mammals that have evolved testicles of all different sizes. In almost all these separate cases, ...

Dominant male lemurs flexibly grow their testicles when other males are around, putting them in a better position to successfully mate. In many species, dominant males have larger testes than ...

Undescended testicles (UT), which is used synonymously with the term cryptorchidism, is characterized as the failure of either one or both testes and their associated structures to descend during ...