How One Bad Science Headline Can Echo Across the Internet

Recent articles claiming birth control causes “transgender” fish show how science communication can mislead—even when it relies on facts

This month, several news outlets misleadingly reported that women's birth control was causing "transgender" fish. / Alamy

The headline sounded like something out of a Margaret Atwood dystopian novel: “Fish becoming transgender from contraceptive pill chemicals being flushed down household drains.” Actually, it was a news article that appeared in The Telegraph, a well-known British newspaper, earlier this month. Its alarmist sentiment quickly spread.

Outlets ranging from the International Business Times to National Geographic Australia to The New York Post picked up on the story and ran with it, also declaring that the estrogen in birth control was resulting in “transgender” fish. These news stories all cited a University of Exeter environmental biology professor named Charles Tyler as the source of this information. Yet the way the sites presented the information was extremely misleading—and not just because Tyler never said these fish were “transgender.”

Yes, endocrine-disrupting chemicals like those found in birth control can cause male fish to produce female proteins and develop eggs in their testes. In 2009, Tyler and co-authors reported that exposing wild roach fish (Rutilus rutilus) to a synthetic estrogen can result in intersex fish. And yes, this is worrisome. These genetic changes have the potential to disrupt fish reproduction, which could in turn can have negative effects on the aquatic ecosystem. 

But two things about all those headlines were very wrong. First, terminology. “Intersex,” the term Tyler and other reproductive scientists use, refers to having a mix of biological sex characteristics, and can apply to humans and other animals. “Transgender,” by contrast, is really only a word that applies to humans and our specific social constructions of gender.

Second, and more importantly: Ladies, your birth control isn’t necessarily what’s driving the problem.

Tyler’s experiments looked at one type of synthetic estrogen: ethinyl estradiol, or EE2, which is found in oral contraceptives like TriNessa and Seasonique. These kinds of one-chemical experiments “are important to make sure you're studying the chemical of interest,” writes Amber Wise, a co-author of a 2011 Environmental Science & Technology paper about this topic, in an email. “But it obviously leaves out consideration of other chemicals.”

“Very few compounds have been studied as closely as EE2,” she points out. In other words, we know that EE2 can cause reproductive imbalances, but we don’t know the effects of other similar chemicals, many of which occur in the environment at exponentially higher levels. “It's common knowledge in the environmental health community that there are tens of thousands of chemicals in consumer products and industrial use that have zero [or essentially no] toxicological data available,” she writes.

So theoretically, any of those chemicals could be having a far greater impact than EE2.

Wise’s paper found that birth control’s contribution to the different types of chemicals that have estrogenic and antiandrogenic—aka testosterone-blocking—effects in our environment is minimal compared to that of other agricultural, industrial and municipal sources. In an email, Tyler agreed that “No one can say that any one chemical or source is exclusively responsible for intersex induction in wild fish.”

Removing the Pill “from the market will have a negligible effect on the environment, aquatic life and human health,” Wise and her co-authors concluded in 2011. However, it “would be detrimental to women’s health and their ability to decide the timing and spacing of their children and would have societal and global implications.”

How One Bad Science Headline Can Echo Across the Internet
Screenshot of The Telegraph's original article on Charles Tyler's research.

This is by no means the first time that news sites or non-scientific organizations have accused birth control of being a harmful pollutant without strong scientific evidence. In 2009, the Vatican’s official daily newspaper L’Osservatore Romano claimed that the Pill harms the environment, according to Reuters. The Vatican article claimed its information was based on a paper written by a Swiss doctor, but provides no quotes nor information about where the paper can be accessed. 

Not long after, the American Life League, an anti-abortion and anti-euthanasia advocacy group, started promoting the idea that chemicals in the Pill harm fish and the environment using the slogan "The Pill Kills." The League cited, among other things, a Scientific American article about one study in which scientists were “unclear exactly what estrogen-mimicking chemicals were actually present in the fish.”

“This sort of thing has come out from very conservative sources over many years, and it is not supported by science,” says Rivka Gordon, a physician assistant who serves as the policy chair of the Association of Reproductive Health Professionals (ARHP). In 2011, Gordon co-authored an editorial in ARHP’s journal, Contraception, about birth control hormones in water. It argued that, “contrary to what has been stated or implied by media reports and anti-contraception advocates, synthetic estrogen from birth control pills is not the sole or primary source of endocrine-disrupting chemicals in water [emphasis theirs].” 

The editorial drew heavily from paper Wise co-authored with researchers at the Reproductive Health and the Environment program at the University of California at San Francisco. That study, conducted in response to claims by the Vatican and others that birth control was a pollutant, concluded that “the contribution of [oral contraceptives] to overall estrogenicity in water is relatively small compared to other natural and synthetic estrogens.”

To be fair, the recent articles blaming birth control for water pollution do acknowledge that other factors contribute to the amount of estrogens or estrogen-like compounds in water. Even the conservative-leaning The Blaze, which also ran a story that placed most of the burden on birth control, stated at the bottom of the article that many chemicals in the water can have estrogenic effects on fish.

Still, Kimberly Inez McGuire, a reproductive justice advocate and communications strategist who co-authored Contraception’s 2011 editorial with Gordon, calls these kinds of stories “irresponsible.” Headlines like The Telegraph’s, she says, are a good example of how news reports on scientific research can be misleading, even when it reports factual information. By omitting other factors, such articles can be used as ammunition in a fraught political landscape, as feminist news site Jezebel recently pointed out in a satirical article titled: “Stupid Ideas: Your Whore Pills Are Polluting Our Pristine Waters and You Should Pay for It.”

“We’re polluting our environment with tons and tons of chemicals every day,” says Wise, a who has a Ph.D. in chemistry and is currently the scientific director at Avitas Agriculture, a cannabis producer and processor and in Washington State. As an example, Wise points out that “we treat our livestock with huge amounts of synthetic hormones to to regulate their reproductive hormones.” Unfortunately, because that information is proprietary, it’s almost impossible to know what’s in these hormones and at what dosage they’re administered.

All people, including men, already naturally excrete different types of estrogens in urine and feces. For pre-menopausal women it’s 16.3 micrograms per day, and for pregnant women it’s 6,859 micrograms, according to Wise’s paper. The Pill can roughly double the level of estrogens a non-pregnant woman excretes per day. But compare that to fertile adult cows, who excrete 299 micrograms per day when they’re not pregnant and 576 to 111,620 when they are.

This data suggests that overall, cows are bigger producers of natural estrogens than humans. In addition, a 1995 study found that in the U.S., “the use of veterinary estrogens was more than five times the use of” human oral contraceptives per year, according to Wise’s paper. Add onto that the fact that human waste flushed down the toilet get treated in wastewater facilities, removing some of these estrogenic compounds, while livestock waste enters the environment untreated.

Still, Wise advises that livestock isn’t the only problem.

“There’re lots and lots of other chemicals, plant estrogens, industrial chemicals, pesticides—all kinds of things that have estrogenic effects and antiandrogenic effects, which are both reproductive modifiers,” she says. Even non-estrogens like BPAs, “found in hard plastics, the lining of tin and beverage cans, and paper receipts,” and brominated flame retardants, “found in all kinds of foam furniture and cushions, plastics, and other consumer materials,” can have detrimental reproductive effects on fish and other animals.

These kinds of headlines also add to the bevy of contradicting information facing women. Misinformation about birth control’s medical side effects is common, and McGuire says that stories erroneously labeling birth control as a major pollutant make it even more difficult for women to get all the facts and make an informed decision about whether to use birth control. These kinds of arguments, she adds, unfairly place the burden on women’s actions, rather than looking at all the factors involved and the different systemic solutions, such as better wastewater treatment, that could address the problem. 

“Oftentimes, an inflammatory headline can not only spread misinformation but it can distract us from the bigger issue,” McGuire says. “Even if we all agree that there is a problem of estrogenic compounds either potentially or actually being in our water, the solution to that should not be putting the responsibility and the onus of this societal problem onto a woman and her personal decisions.”

Get the latest Science stories in your inbox.