Plurality of opinion, scientific discourse and pseudoscience: an in depth analysis of the Séralini et al. study claiming that Roundup™ Ready corn or the herbicide Roundup™ cause cancer in ratsby Gemma Arjó, Manuel Portero, Carme Piñol, Juan Viñas, Xavier Matias-Guiu, Teresa Capell, Andrew Bartholomaeus, Wayne Parrott, Paul Christou

Transgenic Res


Agronomy and Crop Science / Animal Science and Zoology / Biotechnology / Genetics



Plurality of opinion, scientific discourse and pseudoscience: an in depth analysis of the Se´ralini et al. study claiming that RoundupTM Ready corn or the herbicide RoundupTM cause cancer in rats

Gemma Arjo´ • Manuel Portero • Carme Pin˜ol • Juan Vin˜as •

Xavier Matias-Guiu • Teresa Capell • Andrew Bartholomaeus •

Wayne Parrott • Paul Christou

Received: 20 December 2012 / Accepted: 2 February 2013  Springer Science+Business Media Dordrecht 2013

Abstract A recent paper published in the journal

Food and Chemical Toxicology presents the results of a long-term toxicity study related to a widely-used commercial herbicide (RoundupTM) and a Rounduptolerant genetically modified variety of maize, concluding that both the herbicide and the maize varieties are toxic. Here we discuss the many errors and inaccuracies in the published article resulting in highly misleading conclusions, whose publication in the scientific literature and in the wider media has caused damage to the credibility of science and researchers in the field. We and many others have criticized the study, and in particular the manner in which the experiments were planned, implemented, analyzed, interpreted and communicated. The study appeared to sweep aside all known benchmarks of scientific good practice and, more importantly, to ignore the minimal standards of scientific and ethical conduct in particular concerning the humane treatment of experimental animals.

Keywords Safety assessment  GM crops 

Toxicity  GM maize

G. Arjo´  C. Pin˜ol

Departament de Medicina, Universitat de Lleida-Institut de Recerca Biome`dica de Lleida (IRBLleida),

Lleida, Spain

M. Portero

Departament de Medicina Experimental, Universitat de Lleida-Institut de Recerca Biome`dica de Lleida (IRBLleida), Lleida, Spain

J. Vin˜as

Departament de Cirurgia, Universitat de Lleida-Institut de

Recerca Biome`dica de Lleida (IRBLleida), Lleida, Spain

J. Vin˜as  X. Matias-Guiu

Hospital Universitari Arnau de Vilanova, Lleida, Spain

X. Matias-Guiu

Departament de Cie`ncies Me`diques Ba`siques, Universitat de Lleida-Institut de Recerca Biome`dica de Lleida (IRBLleida), Lleida, Spain

T. Capell  P. Christou (&)

Departament de Produccio´ Vegetal i Cie`ncia Forestal,

Universitat de Lleida-Agrotecnio Center, Lleida, Spain e-mail:

A. Bartholomaeus

School of Pharmacy, University of Canberra, Canberra,


A. Bartholomaeus

Therapeutic Research Unit, School of Medicine,

University of Queensland, Brisbane, Australia

W. Parrott

Department of Crop and Soil Sciences, Institute for Plant

Breeding, Genetics and Genomics, University of Georgia,

Athens, GA, USA

P. Christou

Institucio´ Catalana de Recerca i Estudis Avanc¸ats,

Barcelona, Spain 123

Transgenic Res

DOI 10.1007/s11248-013-9692-9


It started with a press conference in which journalists agreed not to engage in fact-checking in return for a preview of new research indicating that both a widelyused herbicide and a genetically modified variety of maize resistant to that herbicide caused high levels of tumors in rats (Butler 2012). Within hours, the news had been blogged and tweeted more than 1.5 million times. Lurid photos of tumor-ridden rats appeared on websites and in newspapers around the world, while larger-than-life images of the rats were broadcast across the USA on the popular television show Dr. Oz.

Activists destroyed a GM soybean consignment at the port of Lorient, France, in order to denounce the presence in the food chain of a product they considered to be toxic (Vargas 2012). The Russian Federation and

Kazakhstan banned imports of the maize variety used in the study, Peru imposed a 10-year moratorium on

GM crops (Bernhardt 2012) and Kenya banned all imports of GM food (Owino 2012).

The corresponding original research article was published in the journal Food and Chemical Toxicology (Se´ralini et al. 2012). The European Food Safety

Authority (EFSA) and its counterparts in Australia,

New Zealand and Canada were quick to criticize the study and its outcomes, and a joint statement condemning the article was released by six French academies (Supplementary References 1, EFSA 2012). The tide of criticism was joined by the competent national authorities in Belgium, Brazil, Romania, France, the Netherlands, Germany and Denmark, as well as numerous prominent scientists attacking the study on ethical, methodological and statistical grounds (Supplementary

References 2). At the same time, some long-term opponents of GM crops heralded the study as proof that current risk-assessment practices are deficient and unsuitable (Supplementary References 3).

In this article, we discuss the many shortcomings of the Se´ralini paper and dissect its erroneous conclusions.

We also discuss the consequences of permitting such poorly-executed research to be reported in the media without challenge, and conclude that the editor of Food and Chemical Toxicology should have retracted the paper based on its clearly flawed data, its breaches of ethical standards, and the strong evidence for scientific misconduct and abuse of the peer-review process. We welcome diverse interpretations of scientific data as long as these are supported by experimental evidence and data analysis, because this is necessary for scientific progress. However, we are highly critical of the flawed science in the Se´ralini paper, and of the irresponsible media reporting surrounding it, which violates internationally accepted professional ethical standards of journalism.

One of the cornerstones of science is communication within the scientific community and with the public. The Se´ralini paper is a regrettable example of failures at multiple levels during the execution and communication of research, including the inability to formulate a valid hypothesis, implement sound and unbiased experiments, analyze the results properly, report the experimental outcomes objectively, allow other researchers access to raw data, and separate accurate observations and conclusions from artifacts.