Intersex is a general term for an organism that has sex characteristics that are between male and female.
[3] Intersexuality can occur due to both genetic and environmental factors[4] and has been reported in mammals, fishes, nematodes, and crustaceans.
Depending on the definition, the prevalence of intersex among humans has been reported to range around a figure of 0.018%.
[13] Gonadal intersex occurs in fishes, where the individual has both ovarian and testicular tissue.
[15] The oldest evidence for intersexuality in crustaceans comes from fossils dating back 70 million years ago.