Gender & Sexual Diversity Education Resources: Variations Found In Nature

Intersex is a group of conditions where there is a discrepancy between the external genitals and the internal genitals (the testes and ovaries).

"In the latest study, smallmouth bass and white sucker fish captured at 16 sites in the Delaware, Ohio and Susquehanna rivers in Pennsylvania had crossed over into a category called intersex, an organism with two genders."

"Something strange is happening to the fish in America's rivers, lakes and ponds. Chemical pollution seems to be disrupting their hormones, blurring the line between male and female. "

"Evolution tends to promote a single optimum male and female phenotype for each species. In a few species, however, evolution has instead resulted in extreme phenotypic diversity, where individuals within a sex display a number of discrete and heritable phenotypes."

"Homosexuality in its myriad forms has been scientifically documented in more than 450 species of mammals, birds, reptiles, insects, and other animals"

"...males can switch between the appearance of a female and that of a male in order to foil the guarding attempts of larger males."

"... in the fowl, Gallus gallus, that males of different social status, which experience different intensities of sexual competition, before and after copulation, have different reproductive phenotypes. Dominant males are more vigilant, feed less, and have larger sexual ornaments than subordinate males. Experimentally manipulating social status revealed that these differences were phenotypically plastic, indicating multiple sexual traits were dependent on the social environment. "