Diethylstilbestrol, the untold story
In the years immediately preceding WW2, a team of chemists in the UK led by biochemist Sir Charles Dodds, embarked on an ambitious project to develop an inexpensive and easily produced manmade version of the main female sex hormone, an estrogen called estradiol.
At that time, the science of chemistry wasn’t yet advanced enough to produce hormones in the laboratory, and so the only way of obtaining them was from natural sources. Because of that, they were astronomically expensive and had very limited availability. Experiments had already shown that estrogens had great potential in women’s medicine, and what drew the interest of Dodds and his team was that a wide range of compounds had weak activity as estrogens (although not enough to be of any use as medicines). They wondered whether, by tweaking the chemical structure, they could produce more potent compounds that would be of use.
Their project was a resounding success, first with the discovery of a compound called hexestrol, and then in 1938, with diethylstilbestrol (or DES). DES was amazingly potent as an estrogen, active at the microgram level, and remains to this day among the strongest of all estrogens ever discovered. It could be mass produced by any competent chemical laboratory from inexpensive precursor chemicals.
Since the work that led to its discovery was publicly funded, DES was never patented, and its formula was made freely available so the whole world could benefit from it. US pharmaceutical giant Eli Lilly quickly seized on DES and made it their own, becoming the main manufacturer and distributor of the drug worldwide. Buoyed by the work of two Harvard doctors, George and Olive Smith, they began aggressively promoting DES for use in pregnancy, as a treatment for preventing miscarriages. From about 1940 onward it was being used on an experimental basis for preventing miscarriages, and usage exploded when, in 1947, the FDA approved it as a miscarriage preventative.
Although a large clinical trial in 1953 showed that DES was completely useless as a miscarriage preventative (and actually made miscarriages more likely), the pharmaceutical industry and the FDA pressed on regardless. It wasn’t until the publication of a paper in 1971, reporting on high rates of a previously very rare cancer (clear cell adenocarcinoma or CCA) in daughters from DES pregnancies, that the FDA finally belatedly withdrew their approval. Many doctors within the US continued prescribing it “off label” for several years after that though, and outside the US, usage appears to have continued unabated throughout the 1970s.
Although there’s far more information publicly available about DES usage in the US than elsewhere, during its heyday, DES was used as the standard treatment for miscarriage prevention throughout the Western world. Over the 4 decades between 1940 and 1980, it’s estimated that it was used in as many as 10 million pregnancies worldwide, most of which resulted in live births.
When doctors Smith and Smith originally came up with the idea of using DES as a miscarriage preventative, it was still a very new compound, and they clearly had no conception of how powerful a drug it actually is. They devised a table of progressively increasing doses that resulted in a comparatively light exposure during the first trimester, but a much heavier exposure during the second and third trimesters. The doses in that table turned out to be insanely high, hundreds of times higher than would be used in estrogen hormone treatment today. Nonetheless, once they’d become part of established clinical practice, those same insanely high doses carried on being used right up until the time DES was withdrawn from use.
To give you an idea of just how much artificial estrogen DES mothers (and their unborn children) on the “Smith and Smith” regimen were exposed to, here’s a quote from DES mother and activist Pat Cody’s book “DES Voices: from Anger to Action”:
By the time I had completed this course of treatment, I had swallowed a total of 10,100 milligrams, or more than ten grams, of DES — roughly the equivalent of 500,000 of today’s low-dose birth control pills.
It sounds absurd, but I’ve fact checked this claim, and it is accurate.
I obtained a copy of the 1953 “Physician’s Desk Reference”, a compendium published annually and distributed to doctors throughout the US, containing the manufacturer’s recommended prescribing information for all the pharmaceuticals on the US market. Here’s the entry for DES:

That same table for preventing “accidents of pregnancy” (i.e. miscarriages) was apparently published every year from 1947 to 1962. Note that those doses are in milligrams, not micrograms! I stuck the table into a spreadsheet, and the cumulative total over the course of a pregnancy actually came to 11,718 mg, not 10,100 mg.
Weight for weight, DES has about the same potency as ethinylestradiol, an artificial estrogen that’s often used in birth control pills (1). I looked at the ingredients information for a number of different brands in the UK of combined oral contraceptive pills, and nearly all the ones that contain ethinylestradiol have 30 micrograms per tablet.
One milligram is a thousand micrograms, so that 11,718 milligrams is 11,718,000 micrograms! Divide it by 30, and that’s the equivalent in artificial estrogen of 390,600 birth control pills! Depending on what assay you use, DES may actually be slightly more potent than ethinylestradiol, so the 500,000 birth control pills claim isn’t necessarily an exaggeration at all. At the very least, it’s certainly in the right ballpark.
The DES mothers, and their children who were exposed to the drug in the womb, are by far the most heavily hormone exposed people on the planet, and it’s not hard to see why so many DES daughters were born with abnormalities of their reproductive tract (hooded cervix and T shaped uterus), why they have unusually high rates of cancer, why so many of them turned out to be infertile, and why some of them went into menopause while they were still in their twenties.
You’d expect the sons from these pregnancies to be badly affected by their exposure too. After all, if an adult man were to consume an average of more than a thousand birth control pills a day for seven months, assuming he survived, he’d experience some quite noticeable effects! He wouldn’t look like a man any more at the end of it, that’s for sure.
So, what is the official position on what happened to the DES sons? According to the CDC, the only known health effect attributable to DES exposure in the sons is an increased likelihood of developing “noncancerous epididymal cysts” of the testicles. No infertility, no increased risk of cancer, no nothing. Just a higher rate of “noncancerous epididymal cysts”. The medical industry and public health bodies like the FDA sure dodged a bullet with that one!
However, there are some dissenting voices, including mine. The opinion I’ve reached since first finding out about DES in 2011, is that many of us are permanently feminised by our exposure, both physically and psychologically. I also think that certain people within the medical industry must have known about this for a long time, and, wary of a possible backlash if word got out that they accidentally created several million people who aren’t really one sex any more, they opted for a cover up. Maybe they think the effect is limited to DES (although I’m pretty sure it isn’t!), and that now DES is no longer used, the whole episode can safely be forgotten.
They’ve been helped by the way DES (and other hormones used for miscarriage prevention) are usually prescribed, which results in little or no exposure during the critical for genital development, so the baby is generally born with relatively normal appearing male genitals. Instead, it’s the brain that bears the brunt of the effects, which carries through to the later behaviour, psychology, and whole inner identity of that person. In my case it’s very much an intersex condition, but most of the people I’ve talked to have an inner identity that’s overwhelmingly female, and are either living as women, or would like to, but their personal circumstances won’t allow it.
In the one study of DES and gender that’s ever been carried out (“Prenatal DiEthylStilbestrol Exposure in Males and Gender-related Disorders, Results from a 5-year study”, Drs Scott Kerlin and Dana Beyer, 2005), more than 150 out of 500 DES “sons” participating in the study had moderate to strong gender dysphoria, or were living as women. For some reason that story was never picked up by the mainstream media though, and few outside the transgender community know about the link between DES exposure and being MTF transgender.
Notes
- Dose-response curves for a number of estrogenic chemicals, taken from a paper assessing several mycoestrogens for suitability as growth promoters in cattle. In the left hand chart, the curves for both ethinylestradiol (curve a) and DES (curve e) are shown, and you can see how they have virtually the same potency (both are extremely potent compounds, active at the microgram level when used as medicines). Ishikawa cells are a cell line derived from a human endometrial cancer, and are apparently one of the best in vitro methods for assaying how estrogenic a given compound will be in the human body.
