Sexual reproduction requires both a male and a female organism, as opposed to asexual reproduction, which only involves one organism. Asexual reproduction is used by several unicellular organisms and plants. Fish and most other animals reproduce sexually. Some creatures, like corals and komodo dragons, have sexual and asexual modes of reproduction. However, as they do not benefit from the genetic variety brought about by sexual reproduction over the long term (over several generations), their capacity to adapt to their surroundings is compromised.

Asexual reproduction is when two separate members of the same species do not interact with one another. Mitosis is the method used by cells to divide, in which each chromosome is replicated before the nucleus divides, giving each new cell the exact same genetic material.