PORTLAND, OREGON—For decades, biologists have marveled at the diversity of penises across the animal kingdom. But in anatomy, as in other fields, females are getting more credit. At a recent symposium ostensibly about the male organ, the complexity of some female genitalia and their role in shaping phallic diversity stole the show. Researchers studying whales, snakes, and other animals are finding that female sex organs have some of the same baroque complexity seen in males. They now see females as active participants in an arms race, likely evolving more complex genitalia to control mating and to create barriers against forced matings—which in turn leads to male countermeasures. They called for more intense looks at how the sex organs interact during copulation and proposed new methods for measuring these organs.

To read the full story, see the 15 January issue of Science.