The human body is complicated. To make it easier to study and understand, scientists and medical researchers divide the body into different systems, such as the immune system, the nervous system, the endocrine system and so on. In reality, these are not watertight compartments and they overlap and influence each other in both very direct and subtle ways. The endocrine system consists of a large number of glands throughout the body that secrete hormones. These glands can be found in many places, from the brain and thyroid to the stomach and genitals. Some key hormones that are secreted by this system is growth hormone, melatonin, oxytocin, insulin, cortisol, adrenaline, dopamine, testosterone, estrogen and many others. These have important biological effects and regulate many crucial processes in the human body.
What determines how much is being secreted? It is a complicated question with an even more complicated answer. To simplify it a bit, it is influenced by both genetics, environment and how much hormone is already in circulation. With the help of e. g. feedback effects, the body is able to keep hormones at a physiologically healthy levels. Hormones typically have their effects by binding to a hormone receptor that activates downstream signalling and biological effects. Hormones receptors are often highly specialized in order to bind to the corresponding hormone to ensure that the system is regulated and not triggered by other things inside and outside of the body. However, this is not a perfect system.
What are endocrine disruptors and what do they do?
Endocrine disrupting chemicals (EDCs) are substances that interfere in different ways with the endocrine system. For instance, some substances can look structurally very similar to endogenous hormones and thus mimic their effects. Others can prevent hormones from binding to the receptor, thus preventing hormones from having their physiological effects. There are also EDs that are more sneaky and alter the production or regulation of hormones and hormone receptors themselves, rather than binding to the hormone receptors.
Why are scientists concerned about endocrine disruptors in nature?
Since the second half of the 1950s, there has been a large increase in the number of artificially synthesized chemical products. Some of these have shown to be endocrine disruptors in certain organisms such as frogs and fishes at high concentrations. Effects of these include e. g. body deformations, males having more feminine traits and females having more masculine traits. However, it is unclear if the doses that humans and many forms of wildlife are being exposed to are high enough to cause discernible harmful effects.
Endocrine disruptors are probably unlikely to be harmful to human health
It is important to study the effects of EDCs on human and wildlife health, but the current scientific knowledge suggests that there is very little clear evidence that EDCs are harmful to humans in doses that humans are likely to be exposed to and those studies that purport to show evidence of harm can only demonstrate small effects on the population level but cannot establish a cause and effect relationship. Although it is not possible to look at all the data here, let us look at two review papers with comparable but slightly different conclusions.
The first paper is Bonde et. al (2016), which is a systematic review surveying a total of 33 epidemiological studies for an association between fetal or infant exposure to EDCs and various negative outcomes of the male reproductive systems. They concluded that “current epidemiological evidence is compatible with a small increased risk of male reproductive disorders following prenatal and postnatal exposure to some persistent environmental chemicals classified as endocrine disruptors but the evidence is limited”. In particular, they could not make any conclusion about cause and effect.
The second paper is Nohynek et. al. (2013) discussed the effects of EDCs on testicular dysgenesis syndrome and noted that contraceptive pills or synthetic estrogens are at least seven orders of magnitude (10000000x) higher than the residual EDCs from e. g. PCPs and these did not cause any harmful effects of fetal exposure. They also discussed many other examples and investigated the possibility for additive effects. Their major conclusions were that “despite of 20 years of research a human health risk from exposure to low concentrations of exogenous chemical substances with weak hormone-like activities remains an unproven and unlikely hypothesis.”. In particular, their major point was that the dosages are so extremely small compared with exposure that we know are safe and that additive effects are unlikely because of differences in absorption and metabolism between EDCs.
The paper that started the research into EDCs were also later retracted and the scientists were found to have been guilty of research misconduct.
So the two major camps within the scientific community appears to be “probably not” and “probably not but maybe sometimes a little bit, so let us research more and find out”. Regardless of which of these two camps turn out to be most strongly supported by evidence, there is absolutely zero scientific evidence whatsoever that exposure to EDCs in the kinds of doses that can be found in products and nature can change the sexual orientation or gender identity of humans. Even if it did, which there is no evidence for, there is no particular reason to suppose that this would be related to brain damage.
LGBT people existed prior to large-scale industrial chemistry
Perhaps the best way to rebut the claims about EDCs and sexual orientation or gender identity is to point out that there have been many lesbians, gay, bisexual and transgender people before the advent of the chemical industry producing whatever potentially endocrine disruptive chemicals anti-LGBT people mention as these were first made during the middle of the 1900s or later. Differences in reported rates of LGBT people in different countries and over time are far more likely to be due to societal acceptance and respect for human rights.
Alleged “concern” about EDCs and LGBT people is often a smokescreen for anti-LGBT bigotry
Let us look at a few examples of the disgusting maelstrom of pseudoscience and anti-LGBT bigotry.
Carey Gillam, the Research Director at the anti-GMO organization U. S. Right To Know, shared the following anecdotal story from a parent called Denise that strongly believed that prenatal BPA exposure has caused all of her child’s “problems”. The following segments stood out:
My son has also been diagnosed with gender dysphoria, which has been linked to in utero exposure to endocrine disruptors when fetal brain development is occurring after the morphogenesis of sex organ development. The UK’s NHS reports referrals for transgender kids have quadrupled over 5 years.
First of all, this is not true at all at the doses that humans are generally exposed to. Second, Denise has apparently not considered the fact that openness and acceptance of transgender people both within the medical community and society at large has increased in the last couple of years. This is probably the reason why referrals have increased.
What is especially concerning is that Denise tells us that her child has difficulty sleeping, anxiety and a lot of headaches. Has Denise ever considered that this is because she does not lovingly accept and support the gender identity of her child, but basically consider the child to be permanently damaged by endocrine disrupting chemicals instead of transgender?
Mercola.com, one of the largest pseudoscientific and alternative medicine websites on the Internet, recently published a post fearmongering about EDCs that were allegedly in fast food and wrongly claimed that it could cause children to become gender-bending. It did not take long before anti-LGBT bigotry showed up in the comment section (written by user bptr12):
“Interference with sexual differentiation in utero”???? Why do people think there are so many more gay guys around now? Because so many more “come out of the closet”? Give me a break. Their voices are obviously reflecting a hormone imbalance. People so are so in denial and ignorant about the how the corporate PROFIT machine is ruining our world now.
As we highlighted before, the fact that more and more people come out as LGBT is because the social and political environment is more LGBT-friendly now than before. There are many countries that are not LGBT friendly and have prison or death for e. g. being gay and not a lot of people are coming out of the closest in those countries, but are instead forced to hide it. By focusing on the voice, the commentator’s view of gay men are obviously limited, because gay men who he has met that did not have a high-pitched voice would just pass by unnoticed.
Endocrine disrupting chemicals are unlikely to have harmful effects on humans in the concentrations that humans are commonly exposed to. In particular, prenatal exposure to hormones from contraceptive pills and synthetic estrogens that are many orders of magnitude higher have not been associated with any harmful effects. Despite this, it is important to continue researching these chemicals, both for human and wildlife health. EDCs do not make humans lesbian, gay, bisexual or transgender and this is not brain damage. It is just a different sexual orientation or gender identity than some people are used to.