The Old World Hookworm is also known as Ancylostoma duodenale. This species reproduces by sexual reproduction. The Old World Hookworm is not hermaphroditic, meaning it doesn't have male and female organs. Instead there are some worms that are males and some worms that are females. When the egg of this worm is fertilized it is still inside the female's body. This is called internal fertilization. The male worm shoots sperm into the reproductive tract of the female. When the become fertilized, they exit through the host's feces. Once the worm grows into an adult, it lives in its host's body and starts the process of reproduction again.
This picture shows the life cycle of an Old World Hookworm.