Endocrine Disruptors and the Transgendered

By Christine Johnson, contributor

Despite popular opinion and negative media portrayals which disparagetransgendered people as being “mentally ill” or making “lifestylechoices,” an increasing amount of evidence is surfacing which islinking the proliferation of endocrine disrupting chemicals (EDC’s) tovariations in gender identity and sexual orientation. In an invitedpaper published in the December 2001 issue of NeuroendocrinologyLetters, Dr. Gunter Dorner outlines the various purported causes oftranssexualism, which fall into two general classes: 1) genetic enzymemutations and 2) so-called epigenetic effects which include stressfulprenatal/postnatal situations and fetal exposure to endocrinedisruptors such as the pesticide DDT and its breakdown products.(www.nel.edu/22_6/NEL220601 R02_Dorner.htm)

The authors studied the prevalence of polycystic ovaries (PCO),idiopathic oligospermia [low sperm count with no identified cause](IO), and transsexualism (TS) in East and West Germany over the last50 years, and correlated increases in these conditions with the use ofDDT in the two countries. They found that after 1960, (when DDT usagewas high) “clearly increased dehydroepiandrosterone sulfate [DHEA-s]levels and ratios to cortisol were found, suggesting again thepossible co-responsibility of DDT and its metabolites for thedevelopment of transsexualism.” They also found that PCO commonlyoccurred in combination with female-to-male transsexualism, and IOtypically occurred in combination with male-to-female transsexualism,suggesting multiple effects from endocrine disruption.

As for the effect of these chemicals on the brain duringdevelopment, several studies have been performed which examinedvarious areas of the hypothalamus—a section of the brain involved ingender and sex—to see if any sex differences were present. In a 1995article published in Nature entitled “A Sex Difference in the HumanBrain and its Relation to Transsexuality,” the authors showed thatmale-to-female transsexuals have female numbers of neurons in a regionof the hypothalamus known as the bed nucleus of the stria terminalis(BSTc). (www.symposion.com/ ijt/ijtc0106.htm) A later study found thata female-to-male transsexual had male numbers of neurons in thisregion, supporting the idea that this brain region is responsible forgender identity in humans. Similar structures have been identified inanimals which corroborate these findings.

Over the last decade, a significant amount of research has beenperformed showing that EDC’s are having a major impact on sexualityand reproduction in wildlife. In the UK, alkylphenols and phthalateshave been identified as the prime suspects for feminized fish in someareas. These chemicals are persistent breakdown products ofalkylphenol ethoxylates, chemicals used in industrial detergents andas inert ingredients in pesticides. In Florida, an extensive spill ofDDT and dicofol in Lake Apopka resulted in male alligators withabnormally small penises, abnormalities of the testes, and alteredlevels of sex hormones. Male gulls in the Great Lakes region of the UShave been found to have “female (ovarian) type structures,” due tohigh levels of DDT and DDE in the eggs. Male Florida Panthers havebeen found to have undescended testicles and a number of reproductiveproblems, and both males and females are found to contain high levelsof several endocrine disrupting chemicals. (For a more comprehensivereview, see Poisoning the Future: Impacts of Endocrine DisruptingChemicals on Wildlife and Human Health atwww.greenpeace.org/~toxics/.—look in the “reports” section)

Regarding the situation in the Northwest, a study was published inEnvironmental Health Perspectives which showed that 84 percent ofgenetically male Chinook salmon appeared to be female in the Columbiariver. Regarding the cause, lead author James J. Nagler of theUniversity of Idaho reports that pesticides and other chemicals thatare estrogenic have been detected in the river and may play a role inthis observed sex-reversal. (www.sciam.com/news/121900/3.html)

In the laboratory, similar results are found when animals are exposedto hormone disrupting chemicals. In her book “Our Stolen Future,”author Theo Colborn relates the story of two Syracuse Universityresearchers, who in 1950 injected roosters with DDT for two to threemonths. They found that the roosters’ testicles only reached 18percent of the size of the controls, and the typical male secondarysex characteristics were significantly suppressed. It is interestingto note that Harry Benjamin, a New York endocrinologist and sexologistwho wrote the first modern work on transsexualism, The TranssexualPhenomenon in 1966, found that 40 percent of his male-to-femaleand 45 percent of his female-to-male patients had some degree ofhypogonadism. (reduced size of testicles/ovaries) Seewww.symposion.com/ijt/benjamin/index.htm.

Despite the 1972 ban on DDT in the US, the chemical and itsmetabolites keep showing up in pregnant women. A 2000 study publishedin the Journal of Clinical Endocrinology and Metabolism measured thelevels of several pesticides in amniotic fluid during the secondtrimester. The authors found that approximately one out of three humanfetuses in Los Angeles is exposed to a DDT breakdown product at“physiologically relevant levels.” They also added “Although we didnot test for adverse health effects in this phase of the study, theconcentrations of contaminants measured are sufficient to be cause foralarm.” (http://jcem.endojournals. org/cgi/content/full/85/8/2954)

However, DDT is hardly the only endocrine disruptor in existence. OurStolen Future’s website (www.ourstolenfuture.org) lists 85 chemicalswhich are known to be endocrine disruptors or classes of chemicalssuch as PCB’s and dioxins, which have many variants. Phthalates areoften used in plastic food packaging to soften them (think margarinecontainer) and Bisphenol-A is used to line metal cans to eliminate themetallic taste and is commonly found in resins, plastics and dentalsealants. Mercury is one of the most widespread EDC’s, being presentin dental amalgam and childhood vaccines, and lead is commonly foundin Seattle water, reportedly due to the corrosion of lead in homeplumbing because corrosive chemicals are used for disinfecting thewater. (www.ci.seattle.wa.us/util/services/waterquality/analysis.htm).

Mercury is a special case, in that it is the only known endocrinedisruptor which is deliberately implanted in the body (typical“silver” dental amalgam contains 50 percent mercury). The pesticides,of which there are many, are intentionally released into theenvironment, often in homes and schools. Additionally, the vastmajority of the 100,000 chemicals currently in production have neverbeen tested for endocrine disruption effects.

So is it a coincidence that since the introduction of the chlorinatedpesticides around 1935-1940 that the rate of transsexualism has beenclimbing steadily? The first generation born after the introduction ofpesticides was also the first generation to have significant numbersof transsexuals. The condition is virtually absent from the UShistorical record prior to 1952, when Christine Jorgensen madeheadlines. Every generation since has had higher and higher rates.Clearly researchers knew that sexual developmental changes wereobserved with DDT in animals as early as 1950, yet this informationwas ignored, deliberately or not. Fifty years later, large numbers andquantities of EDC’s are being distributed around the globe withoutadequate consideration of the consequences.

This line of inquiry which is examining the relationship between EDC’sand transsexualism has an obvious relationship to the civil rights andsocial perceptions of transsexuals. It will likely lead towardrestoration of full civil rights as the law catches up with emergingscience, and should also increase understanding among the generalpublic as more evidence is uncovered and as doctors improve theirunderstanding of the specific biochemical changes and structuraleffects that are associated with exposure to EDC’s duringdevelopment.