Conspiracy theories emerged in the 2010s alleging that governments were introducingendocrine disrupting chemicals into the water supply to increase thelesbian,gay,bisexual,transgender orqueer (LGBTQ) population. The claim was popularized by conspiracy theoristAlex Jones, who cited studies on the herbicideatrazine, known to induce spontaneous sex reversal orhermaphroditism in certain frog species, to assert that theU.S. government was "putting chemicals in the water that turn the friggin’ frogs gay" as part of a "chemical warfare operation".[1] Spontaneous sex change is a naturally occurring phenomenon in some frog species even in unpolluted environments.[2]
Inanimal studies, exposure to endocrine-disrupting chemicals during gestation can interfere with prenatal hormones and consequentlysex differentiation of the brain.[3][4] This has led some scientists to speculate about the impact of endocrine disruptor exposure during humanpregnancy on latersexual orientation orgender identity, though evidence is currently lacking.[3][4][5]
Animal testing in the 2000s suggested that the herbicideatrazine, anendocrine disruptor, may have afeminizing effect on male frogs causing them to become hermaphrodites.[6][7] Other research failed to reproduce these results in frogs,[8][9][10] though reports of reproductive impact has been reported for other animals, and a meta-analysis conducted in 2010[11] on selected amphibians and freshwater fish showed sublethal reproductive effects at ecologically relevant concentrations. Reviewing 19 studies in total, the United StatesEnvironmental Protection Agency concluded in 2013 that atrazine has no consistent effects on development in amphibians.[8]
According to Lambert and Packer:[2]
A direct link between EDCs and sex-reversed frogs has been observed only in the laboratory, not in the wild. What’s causing sex reversal in these wild frog populations is not yet clear, but our latest data suggest that natural temperature variation, occurring independently of urbanization or climate change, may be a catalyst.
In 2015, American conspiracy theorist and radio personalityAlex Jones claimed that atrazine had caused a majority of frogs in the US to become homosexual, and that the US government was waging a "chemical warfare operation" to increase rates of homosexuality and decrease birth rates.[12][7] This claim goes far beyond what was reported in the scientific literature.[9][13] A quote from Jones's monologue, "I don't like 'em putting chemicals in the water that turn the friggin' frogs gay!" subsequently became aninternet meme.[1]
The idea of a link between atrazine and sexual development was later revived by Americanenvironmental lawyer andanti-vaccine activistRobert F. Kennedy Jr., during his2024 presidential campaign. In various podcast appearances, Kennedy claimed that atrazine contamination was causing widespreaddelayed puberty orprecocious puberty in the Midwest, and speculated that it was causing "sexual confusion" and "gender confusion" in children.[14] Kennedy's theory was criticized in various popular media outlets.[5][15]
Scientific consensus, as summarized in a 2016 review inPsychological Science in the Public Interest, is that there is "no persuasive evidence that the rate of same-sex attraction has varied much across time or place".[16] In contrast to claims about chemicals in the water, the effects of hormones on sexual orientation appear to occur at the prenatal stage, during organization of the brain.[16] Endocrine disruptor exposure duringfetal development has been shown to affectsexual differentiation of the brain in animals,[4] however any effect on human sexual orientation or gender identity requires further research.[4][3]
Recent data show that environmental compounds during early development may interfere with sexual differentiation of the human brain. Plastic softeners, that is, phthalate esters, are pervasive environmental chemicals with anti androgenic effects. Exposure to these compounds is accompanied by reduced masculine play in boys (Swan et al. 2010). Higher prenatal polychlorinated biphenyls (PCB) levels were related with less masculine play in boys, while higher prenatal dioxin levels were associated with more feminized play in boys as well as in girls (Vreugdenhil et al. 2002). The effect of such environmental endocrine disruptors on sexual differentiation of brain systems should be further studied in future.
In particular, the hypothalamus and other sexually dimorphic brain areas are highly sensitive to endogenous sex hormones, and this may determine their vulnerability to EDCs' exposure during critical periods. This evidence could lead to hypothesize a possible etiological link between prenatal exposure to EDCs and the development of sexual orientation and core gender identity. Indeed, Bejerot et al. (2011) suggested a hypothetical link between EDCs and gender dysphoria, speculating about a possible role of phthalates (Bejerot et al. 2011). Phthalates are contained in many plastics, and their environmental concentrations have significantly increased in the last few years. Fetal exposure may lead to an increased androgen exposure, increasing the risk of developing gender dysphoria. However, this specific association has never been evaluated before and most of our knowledge is based on data from rodent studies. For this reason, more systematic investigations are required to establish EDCs' interference with sexual differentiation of the brain in determining sexual orientation and gender identity.
The most common meaningful controversy across time and place has concerned the extent to which homosexuality is socially influenced and, more specifically, whether or not it spreads as a result of contagion and social tolerance. There is no good evidence that either increases the rate of homosexual orientation, although tolerance may facilitate behavioral expression of homosexual desire.
