Woman who knew too much

by Yeong Sek Yee & Khadijah Shaari

This biography illuminates the life and achievements of a remarkable woman scientist who revolutionized the concept of radiation risk.  Written by Gayle Greene, who was the Professor of Women’s Studies and Literature, Scripps College, UK, the book is compelling reading for activists and policy makers.

In the 1950s Alice Stewart began research that led to her discovery that fetal X rays double a child’s risk of developing cancer. It was towards the end of 1955 that Dr. Alice Stewart, head of the Department of Preventive Medicine at Oxford University, first became aware of a sharp rise in leukemia among young children in England. Dr Stewart subsequently discovered that the number of children dying of this cancer of the blood had risen over 50 percent in only a few years. In the United States an increase about twice as large had occurred. One aspect of this rise was extremely puzzling: the leukemia seemed to strike mostly children over two to three years of age.

Dr. Stewart undertook another study to find out. With the assistance of health officers throughout England and Wales, she obtained detailed interviews with the mothers of all of the 1694 children in those counties who had died of cancer in the years 1953 to 1955, as well as with an equal number of mothers of healthy children. By May 1957, the analysis of 1299 cases, half of which involved leukemia and the rest mainly brain and kidney tumors, had been completed. The data showed that babies born of mothers who had a series of X-rays of the pelvic region during pregnancy were nearly twice as likely to develop leukemia or another form of cancer, as those born of mothers who had not been X-rayed.

Subsequently, in a research paper she published in June 1958, Dr. Stewart concluded that the dose from diagnostic X-rays could produce a clearly detectable increase in childhood cancer when given during pregnancy and this was an extremely low dose. However, it took until 1980 before the major American medical groups recommend that doctors not routinely x-ray pregnant women—and even so, 266,000 pregnant women were x-rayed in that year. Dr Stewart believes that “it takes about 20 years…for an unpopular discovery to be digested and you’re lucky if it takes only that long.”

There were a few other very unpopular discoveries made by Dr Stewart and her team of researchers. Some of these are:

  • Radiation is the most powerful mutation known to man, a poison that no one can feel, smell, see, or detect until people drop dead.
  • There is no safe level of radiation…her research clearly debunked the universally accepted “threshold hypothesis” that claimed that there was a threshold below which radiation was safe.
  • Any dose of radiation, however small, is going to have an effect in the bodyany dose has the potential of damaging a cell…low dose may injure cells rather than kill them…and a surviving mutated cell can cause cancer or a birth defect.
  • Lower doses received over time might actually produce more cancer per unit of exposure than a single large dose. Dose fractionation increases the cancer risk.
  • Even more than the cancer threat is the genetic damage—the possibility of sowing bad seeds into the human gene pool…and the danger with recessive genes is that once they are into the gene pool, you can’t get them out.
  • Radiation damage to a cell may show up only after the cell has divided several times, producing a genomic instability that might result in broken or misshapen chromosomes and muted genes and early cell death.
  • Researchers found that children whose fathers were exposed to the highest levels of external radiation were six to eight times more likely to develop leukemia than were the controls…in other words there is a correlation between paternal exposure to radiation and childhood cancer.

As a woman scientist, she faced a significant amount of prejudice and ridicule from the male-dominated scientific community, and other groups who found it hard to accept the findings of her research that radiation was harmful even in low doses to unborn fetuses. Despite all this, she stood by her studies and research and eventually convinced doctors to stop x-raying pregnant women even though it took twenty years to eradicate the practice.

From about 1970, Stewart turned her attention to the underlying issue raised by her work: the serious underestimation, in her view, of the risks of exposure to radiation in nuclear power plants. She again astounded the scientific world with a study showing that the U.S. nuclear weapons industry is about twenty times more dangerous than safety regulations permit. The finding put her at the center of the international controversy over radiation risk.  Dr Stewart became one of a handful of independent scientists whose work is a lodestone to the anti-nuclear movement. In 1990, the New York Times called her “perhaps the Energy Department’s most influential and feared scientific critic.”

With her life time research experience in the field of radiation, Dr Stewart had a firsthand knowledge of the misuses and politicization of radiation science. The radiation field is so politicized, there is so much invested, ideologically and economically, that these scientists just cannot change their mind. They simply cannot say, “We may have been wrong.”

Politicized the field has been, and politicized the field remains. The Atomic Energy Commission had strong vested reasons for downplaying the effects of radiation and maintaining a safe threshold theory and continues to argue that low doses of radiation are negligible.

Marginalized by mainstream British medical research, starved of funding, blackballed, blacklisted, cold-shouldered, she has borne with more than her share of slights, snubs, and rebuffs. In her parting remark in the biography, Dr Stewart said, “If I were GOD tomorrow, I should take every job away from the nuclear physicists”

Dr Alice Stewart died in June 2002 at the age of 95. With her passing, gone are the days of researchers like Alice Stewart.



2)      Early Life Exposure to Diagnostic Radiation and Ultrasound Scans and Risk of Childhood Cancer: Case-Control Study


3)      Alice Stewart, 95; Linked X-Rays to Diseases


The Woman Who Knew Too Much: Alice Stewart and the Secrets of Radiation


The Unheeded Warning


 The Woman Who Knew Too Much


Obituary: Alice Stewart … The Guardian



1)      YOUTUBE: Alice Stewart: The woman who knew too much


2)      YOUTUBE: Dr. Ernest Sternglass on Radiation & Health