The nematode Caenorhabditis elegans¶

The nematode Caenorhabditis elegans is normally hermaphroditic, with a germline that produces both sperm and eggs. It uses its own sperm to self-fertilize its own eggs, which it then lays to produce new hermaphroditic offspring.

About 1 in every 200 worms develops male instead. https://t.co/pJ8h7TGJN8 The male C. elegans is smaller, has a differently-shaped tail, and produces only sperm. It probes around the hermaphrodite vulval region with its tail, inserts its sperm, and thereafter, the hermaphrodite will then preferentially use the male's sperm rather than its own. The rate at which males appear in the population is heavily determined by the environment. When resources are scarce, a hermaphrodite will lay more XO (male) eggs. This points to the evolutionary role of sexual reproduction as a tool for adapting to environmental stress. There are a million more examples of the weird and wild diversity of sex in both the plant and animal kingdoms that I could list off the top of my head. I just wanted to highlight C. elegans because they are strange and cool (and one of the most commonly used model organisms)! This guy clearly does not have a PhD -- or probably even a bachelor's -- if he thinks "binary" is a remotely applicable term to the topic of sex.