In the animal kingdom, penises can be spiked, split, corkscrewed—even detachable. They're one of the most diverse structures in biology. The human penis is so uniform, it's an anatomical outlier.

New research has mapped the cell types that specialize to form reproductive organs in both sexes, identifying key genes and ...

Michelle Spear does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond ...