TISM

Toxically Induced Sexual Morphism is the central plot device of the Ridgewick Chronicles. A genetic disorder caused by environmental contaminants, TISM causes mutations in the Five-Alpha Reductase gene (5ar), altering fetal DNA in utero. Higher levels of the toxin can cause death, still-birth and severe abnormalities; lower levels can lead to sterility and infertility in human beings.

An extremely rare side effect of TISM is form of pseudo-hermaphrodism in afflicted males, in which the chromosome is "overwritten" by the endocrine system, giving the subject a hyper-feminized appearance.