Reporting embryonic stem cell science

Muscle cells grown from embryonic stem cells Copyright: Flickr/coleman and caroline

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Luisa Massarani offers tips on how to navigate your way through the highly controversial world of embryonic stem cell research.

The stem cells from embryos (embryonic stem cells, or ESCs) have an extraordinary property: they can develop into any of the body’s highly specialised cells, a process known as differentiation. This characteristic, say scientists, could offer treatments for a range of diseases from diabetes to Alzheimer’s.

And that generates many column inches from journalists; from breathless wonder at ESCs’ possibilities, to condemnation of a science that destroys a human embryo.

ESC research is one of the most complex science topics to cover. Despite its potential, the benefits are unlikely to be felt for decades. It is not without risk and it engenders deep passions on both sides.

There is no simple formula for reporting stem cell science. But here are a few rules to help ensure your coverage is responsible and informative. They are based on my experience of covering controversial ESC research in Brazil.

Get the basics right

Before you can report on ESC research, you must understand the concepts and terminology, so you can translate them for your audience.

A stem cell is a cell that can divide for indefinite periods in culture and is at least ‘multipotent’ — it can give rise to specialised cells (such as neurons or skin cells).

There are two main types of stem cell and it is vital to tell your audience which you are referring to.

Embryonic stem cells are undifferentiated cells derived from a four or five day embryo that can divide in a culture for a prolonged period without necessarily developing into specialised cells. They can develop into all cells and tissues, as well as other ‘extra-embryonic’ tissues such as the placenta — they are ‘totipotent’.

Adult stem cells are undifferentiated cells found in many organs and differentiated tissues. Their ability to divide in culture is more limited than ESCs and they usually differentiate only into cell types in the organ of origin — they are ‘multipotent’.

ESCs are useful for studying genetic disease. The genetic material of a cell from a cystic fibrosis patient, for example, can be transferred into an unfertilised egg cell with its own genetic material removed.

This new egg is stimulated to divide, producing the embryo from which ESCs with the genetic indicators of cystic fibrosis can be taken and studied. This usually means destroying the embryo, though researchers have recently found ways of extracting stem cells without doing so.

But the main focus on ESCs — particularly for the media — is their potential to treat disease. ESCs offer more promise than do adult stem cells because they can become any cell.

In a treatment scenario, ESCs might be taken either from an embryo made as just described — so-called therapeutic cloning — or from an embryo left over from fertility treatment. The ESCs would be stimulated in the laboratory to grow a particular cell type that could be implanted into a patient. For example, nerve cells implanted into a damaged spinal cord might repair it, allowing the patient to walk.

ESC research is controversial because in all cases, it uses an embryo. And creating ESCs from unfertilised eggs is also the first step to making a full living copy of an organism, or ‘reproductive cloning’. For these reasons, campaigners have protested against the technology and accused scientists of ‘playing God’.

In 2006, researchers made another breakthrough. They identified conditions that would reprogramme some specialised adult cells to become like stem cells. This new type of cell is called an induced pluripotent stem cell (iPSC). They could provide an alternative to ESCs if they are indeed ‘pluripotent’ — able to differentiate into all types of human cells.

If you are unsure about any of the technical issues or definitions, refer to reliable sources such as the US National Institutes of Health stem cell information.

Do not give false hope

People are naturally most interested in how research might affect their lives, so the potential for ESCs to treat diseases gets a lot of media coverage. But although ESC experiments in animals are encouraging, no clinical trial has yet been performed in humans and it could be decades before therapies based on ESCs reach the clinic.

Don’t give people false hope. Double check the stage of the research and make it clear to your audience how much more needs to be done to make treatments a reality.

Adult stem cells are the only type of stem cell to be used in treatment



Answer some basic questions. Is it an experiment in the laboratory? Does it use cells or animal models? Has it been applied to humans? How large is the study? When could patients receive such a treatment?

Communicate the excitement of advances in ESC research, but do not let this ‘wow factor’ override the reality: long waits for treatments.

Learn from the Brazilian case. Pro-ESC stakeholders did not communicate until after legislation allowing ESC research was passed that it could be decades before the research benefits society, causing public outrage.

Report the drawbacks

Journalists often ignore the risks and possible side effects of ESC therapy. For example, studies have shown that undifferentiated ESCs can form cancerous clusters of cells called teratomas when injected into mice. 

Injected ESCs might also be rejected by the body, much like any transplant. While creating ESCs with a patient’s own genes (as in therapeutic cloning) reduces this risk, it may not always be practical, for reasons such as a shortage of donor eggs.

Always ask researchers what could go wrong. Your audience will understand that many treatments have side effects — chemotherapy for cancer for example. Don’t shy away from them to make a story more exciting.

Understand the context

It is also important to understand the local context. Be familiar with what is happening in your country. Is there legislation on ESCs? What exactly does it say? Is the topic controversial? Is there much research being done by local scientists using ESCs or adult stem cells?

Adding a paragraph about the issue in your country will help your audience understand how a particular piece of research might affect them. Some countries allow all kinds of ESC research (except for reproductive cloning), while others, such as Brazil, allow research only on embryos discarded from fertility treatment.

You might find reporting on ESC policy just as complicated. In Brazil, for example, the biosafety law allowing ESC research included another controversial issue, GM crops. And in the UK, amendments to ESC research policy went through parliament on the same bill as a motion to reduce the legal time limit on abortions.

See SciDev.Net‘s practical guide for more tips on how to cover science policy.

Remain objective

Embryonic stem cell research divides the public

Flickr/Jun Seita

On such highly divisive issues you must strive to remain objective. The public is already dealing with the views of warring parties, without having to contend with a journalist’s own agenda too.

Aim for balance, but avoid false balance. You do not always need to get general comments about either the massive potential or great evil of ESC research — try not to present the issue as black and white.

Instead find interviewees who will give measured, specific opinions about the research you are reporting. Do other scientists in the same field agree with the researchers’ claims for example? Can they foresee obstacles between the research and the clinic?

When finding interviewees, remember that scientists are only human too. Ask yourself why people might say what they do — does the lead researcher own a company planning to commercialise the technology? Is the external commentator who casts doubt on the research’s validity simply vying for more funding for adult stem cell research instead?

Also, consider the situation in your country. Avoid giving conflicting voices the same weight if that does not reflect views where you live. For example, in a country where most people are for ESC research, think carefully about how much weight to give the lone dissenting voice.

Similarly, try not use emotive language — either for or against ESC research. You might think you are being objective but you could unwittingly sway the reader with your choice of words.

Remember how far adult stem cell research has come in the last few years. Adult stem cell therapies, such as stem cell transplants for blood cancers, are the only therapies yet to have made it to the clinic. iPSCs might also become an alternative to ESCs.

Journalists are often accused of ignoring the potential of adult stem cell research and being too close to ESC researchers. If appropriate, ask whether adult stem cells could achieve the same aim, or try to find out how far scientists have got.

And even if images and headlines are mostly outside your control, urge caution. For example, an important Brazilian newspaper used a front-page photo that, because it was taken from below, seemed to show a religious fanatic oppressing a man in a wheelchair. Guard against bad headlines or a photo destroying your carefully prepared and balanced story.

Expressing an opinion

If you cannot resist putting your opinion on the subject into print — in an opinion article for example — there are a few things you must do.


Do your research. Whether you favour or oppose ESC research, be sure that you carefully consider all the key issues and evidence. Don’t be manipulated one way or the other.


Clearly define what is your opinion and what is fact. Never dress up your opinion as objective reporting. And avoid mocking those who have a different view. In Brazil, for example, journalists accused ESC opponents of being religious extremists, or deliberately vague because they cannot understand the science.

Finally, even though many stories about ESC research will be too short to cover all the topics discussed here, keep these pointers in mind. They will balance and steady your reporting.

As I have tried to show in this guide, stem cell research is among the most difficult topics for a science journalist to cover. But it is fascinating for exactly these reasons too.

Luisa Massarani is Latin America and Caribbean coordinator for SciDev.Net and researcher at Museum of Life, House of Oswaldo Cruz, Fiocruz, Brazil.