Earthworms are described as hermaphrodites because they possess both male and female reproductive organs within the same individual.

However, they cannot self-fertilize. Here's why:

* Simultaneous hermaphroditism: Earthworms have both male and female reproductive organs, but they mature at different times. This prevents self-fertilization.

* Cross-fertilization: Earthworms reproduce through mutual fertilization, where two worms exchange sperm. They align their bodies, and each worm inserts its penis into the other's seminal receptacle, depositing sperm.

So, even though they have both male and female organs, earthworms require another individual to reproduce.