Anyone can find another species of beetle, but it’s rare to find a new species of mammal, which are a lot harder for nature to hide. But scientists are announcing this evening that they have discovered a species of elephant shrew that until now somehow managed to escape anyone’s notice.

Elephant shrews, which evolved in Africa some 100 million years ago and have never left the continent, are so named because of their long, flexible snouts. (Ironically, genetic analysis has recently found that they are actually more closely related to elephants than to shrews; other kinfolk include sea cows and aardvarks.) Scientists knew of 15 species, but now Galen Rathbun of the California Academy of Sciences and collaborators have found a 16^th, as they report in The Journal of Zoology. It's the first new one discovered in 126 years.

Named the gray-faced sengi (Rhynochocyon udzungwensis), the new species weighs about 700 grams (1.5 pounds), more than 25 percent more than any other elephant shrew. It lives only in two high-elevation forests in the mountains of south-central Tanzania. It has a distinctive gray face and a jet-black lower rump—and shows yet again that nature still harbors secrets from nosy scientists.

The following letter was received after the Center for Consumer Freedom (CCF) disputed a New York Times report on high mercury levels in tuna sushi and a post on this blog about the Times story.

There is no longer a need to debate whether the writings of journalists such as Sharon Begley (NEWSWEEK) and Marian Burros (The New York Times) are credible or biased, because there is a global consensus among scientists addressing the toxicity of mercury, its sources and the implications of both on public health. This consensus has been documented and is available to the public. As it turns out, their writings are consistent with that consensus.

Last year, many of us joined over 1,000 of the world’s foremost mercury experts for the International Conference on Mercury as a Global Pollutant. Together we developed a consensus declaration that addresses some of the specific points that have been raised here and elsewhere in the discussion around the New York Times article and the Oceana/Mercury Policy Project study. Many of us also have published peer reviewed scientific papers on the subject.

While the consensus declaration was not cause for tremendous alarm, it clearly highlighted the need to recognize that mercury levels in fish are cause for concern and that sensitive populations should choose low mercury fish in order to get the benefits of seafood while avoiding the risks of mercury. The consensus included the following points summarized below: 

1. About two thirds of the mercury in our environment is derived from human activities.
2. Mercury is highly toxic, biomagnifies in the aquatic food web and places humans at risk if they consume high levels of fish that are high on the food chain.
3. In many populations there is evidence that current levels of exposure are sufficient to affect several physiological systems and as a result current mercury exposure levels constitute an important public health problem.
4. Methylmercury affects nervous system development and there is sufficient evidence to warrant the prudent selection of fish in the diet, specifically for pregnant women and children.
5. Long-lasting effects of fetal methylmercury exposure have been documented in children throughout the world.

Rather than following the selective science approach, and chasing down one or two studies that support a particular viewpoint, we recommend anyone who is truly interested should benefit from the full weight of the evidence by reading the scientific consensus in the Conference Declaration which is available here:

http://www.mercury2006.org/portals/31/Mercury2006_conferencedeclaration.pdf

Sincerely,

Henry A. Anderson, MD
Chief Medical Officer
Wisconsin Division of Public Health
PO Box 2659
Madison, WI 53701

H.Vasken Aposhian,  PhD
Professor of Molecular and Cellular Biology
Professor of Pharmacology
LSSB Rm 444
The University of Arizona
PO BOX 210106
Tucson, AZ 85721-0106

David R. Brown Sc.D.
Public Health Toxicologist
Faculty member
Applied Ethics
Fairfield University
Fairfield, CT

Richard W. Clapp, D.Sc., MPH
Professor
Boston University School of Public Health
Boston, MA 

Prof. Dr. Ralf Ebinghaus
Department for Environmental Chemistry
Institute for Coastal Research
GKSS Research Centre Geesthacht
Germany

Philippe Grandjean, MD, PhD
Adjunct Professor of Environmental Health
Department of Environmental Health
Harvard School of Public Health
Boston, MA

Wendy J. Heiger-Bernays, PhD
Associate Professor
Department of Environmental Health
B.U. School of Public Health
715 Albany St. T4W
Boston, MA 02118

Jane Hightower, MD
California Pacific Medical Center
2100 Webster Street Suite 418
San Francisco, CA 94115

Tord Kjellstrom, Med Dr, PhD, MEng
Visiting Fellow
Australian National University
Canberra, Australia

Lynda Knobeloch, Ph.D.
Research and Toxicology Unit Leader
Wisconsin Division of Public Health
1 West Wilson St,  Room 150
Madison, WI 53703

Kathryn R. Mahaffey, Ph.D.
Research Professor
Boston University School of Public Health
Boston, MA  USA

Peter Maxson
Director
Concorde East/West Sprl
10 ave. René Gobert
B-1180 Brussels, Belgium

Donna Mergler PhD
professeure émérite
CINBIOSE,
Centre Collaborateur OMS-OPS pour la prévention des maladies reliées au travail et à l'environnement
Université du Québec à Montréal
CP 8888 succ Centreville
Montréal, Québec, Canada H3C 3P8

Dave McBride
Toxicologist
Office of Environmental Health Assessments
Division of Environmental Health
Washington State Department of Health
PO Box 47846
Olympia, WA  98504-7846

John Munthe, PhD
Department Head
IVL Swedish Environmental Research Institute
Gothenburg
Sweden

Lewis Pepper, MD, MPH
Boston University School of Public Health
715 Albany Street, T 4 West
Boston, MA 02118

Darren Rumbold, Ph. D
Associate Professor of Marine Science
Depart. of Marine and Ecological Sciences
Florida Gulf Coast University
10501 FGCU Blvd. South
Fort Myers, FL 33965

Ellen K. Silbergeld, PhD
Professor, Environmental Health Sciences
Johns Hopkins University
Bloomberg School of Public Health
615 N Wolfe Street, Rm E6644
Baltimore MD 21205

Alan H. Stern, Dr.P.H., D.A.B.T.
Adjunct Associate Professor
Dept. of Environmental and Occupational Health
University of Medicine and Dentistry of New Jersey-School of Public Health

Raphael Stricker, MD
California Pacific Medical Center
450 Sutter Street
Suite 1504
San Francisco, CA 94108

Leonardo Trasande, MD, MPP
Assistant Professor
Departments of Community and Preventive Medicine and Pediatrics
Mount Sinai School of Medicine
NY, NY

Pál Weihe MD
Chief Physician
Department of Occupational Medicine and Public Health
The Faroese Hospital System
The Faroe Islands

Roberta F. White, PhD, ABPP/cn
Professor and Chair, Department of Environmental Health
Boston University School of Public Health
715 Albany St.—Talbot 4W
Boston, MA 02118

If you’re still using polycarbonate baby bottles, sippy cups and juice bottles despite their propensity to leach the dangerous compound bisphenol A, as my colleague Anne Underwood explains in the Feb. 4 issue, at least don’t fill them with really hot water.

Bisphenol A is what’s called an environmental estrogen. That means it acts like a hormone, which may not be what you want for your fetus, baby or toddler. Hundreds of studies on lab animals find that exposure to even minute amounts of bisphenol A can trigger cancer of the breast or prostate years later, reproductive abnormalities and behavioral changes. There are no conclusive data on people, though there’s no doubt we’ve (almost) all become walking chemical cabinets: federal scientists find that 92 percent of us ages 6 and up harbor measurable amounts of bisphenol A. Anyone who wants to wait around for definitive human data, be my guest. For everyone else, some tips:

• Scrubbing or dish-washing polycarbonate baby bottles releases bisphenol A, tests have long shown.
• New data reveal that boiling-hot water increases that rate of release markedly. Even brief exposure to boiling water raises the rate of release by a factor of 15 to 55, scientists led by Scott Belcher of the University of Cincinnati report today in the journal Toxicology Letters. Before exposure to boiling water, the rate of release from individual bottles ranged from 0.2 to 0.8 nanograms per hour. After exposure, rates increased to 8 to 32 nanograms per hour.

There are more and more non-polycarbonate (and therefore bisphenol A-free) baby bottles on the market. That’s the only kind Whole Foods sells, for instance. But if you can’t or won’t buy those, at least wash yours gently in only lukewarm water. No child needs a dose of hormone with her apple juice.

By all rights, chimps and humans should be a lot more similar than we are, considering that our DNA sequences are just under 99 percent identical. But as geneticists keep discovering, just as which music you hear depends not only on what you’ve loaded onto your iPod but also on which tunes you actually play, so what matters in DNA isn’t so much which genes you have as which ones are expressed.

Curiously, scientists now report, which genes are expressed depends, at least in part, on what you eat.

We humans eat much more meat and fat than chimps do, and also cook our food. Researchers at the Max Planck Institute for Evolutionary Anthropology in Germany therefore fed laboratory mice different human and chimp diets for two weeks. The mice ate raw fruits and vegetables like chimpanzees in zoos get, or a human diet of food from the Institute cafeteria, or a pure fast food menu from the local McDonald’s.

Result: the different diets led to remarkable changes in which of the mouse genes were turned on, the scientists report this evening in the journal PLoS ONE. There were thousands of differences in the levels at which genes were expressed in the mouse livers but, interestingly, not in the mouse brains. Many of the genes that changed in the mouse livers are known to differ between humans and chimpanzees, suggesting that these differences might be caused by the difference in human and chimpanzee diets.

Obviously what you eat doesn’t determine which species you are (though we know some vegans who are looking a little simian lately). The scientists calculate that diet accounts for expression differences of 4 percent to 8 percent in the mice’s liver genes, whereas the amount of expression difference between humans and chimpanzees is 15 percent. But it is one more clue to how such small genetic differences can produce species are different as chimps and people.

Lots has been written about why people believe things that fit their worldview even when those things have been disproved time and again (Iraqi weapons of mass destruction, anyone?). But there is a more benign form of this pathology, in which people would rather believe a “good story” than know whether it’s true or not.

This hit me when a friend emailed a film clip of what purports to be a charming music machine, built at the University of Iowa. To me, it looked computer generated, and indeed about three seconds of searching showed that it was yet another urban legend. The surprising part was how the sender, as well as those I had passed it on to myself, reacted when I pointed this out.

The essence was, “thanks a lot for bursting my bubble. I enjoyed it a lot and wanted other people to enjoy it, too. Now you’ve ruined it.”

What struck me about this was that intelligent, science-aware people want to believe cute stories, and are disappointed (even irate) if “science” (me) points out that the story isn’t true. The attitude is, “Who cares if it’s true?”

There seems to be a near-universal human need to hear (and tell, and believe) a good story, regardless of its truth. I’ll leave it to you to think how this can be exploited by, among others, prosecutors (by telling a more compelling story, they can lead juries to convict the innocent) and by cynical and manipulative political leaders.

But here’s one hint. In a 2005 study, scientists found that what you remember and believe about events during the Iraq war depends on your political views. Do you recall a suicide bomber nearing a Najaf checkpoint and blowing up U.S. soldiers? The execution of coalition POWs by Iraqis? The civilian uprising in Basra against Saddam’s Baathist party? All were initially reported by the press, but the last two were quickly retracted as being products of the fog of war.

Yet Americans (especially those who supported the invasion) tend to believe that the last two events occurred even when they recall the retraction. Germans and Australians who recall the retraction, in contrast, no longer believe the misinformation. “People build mental models,” Stephan Lewandowsky, a psychology professor at the University of Western Australia, Crawley, who led the study told me in 2005. “By the time they receive a retraction, the original misinformation has already become an integral part of that mental model, or world view, and disregarding it would leave the world view a shambles.” People therefore “continue to rely on misinformation even if they demonstrably remember and understand a subsequent retraction,” he and colleagues wrote.

The late New York Sen. Patrick Moynihan famously said that people are entitled to their own opinions, but not to their own facts. Believing in the magical music machine is obviously of less concern than believing erroneous information about the Iraq war. But the two beliefs show that people who care about facts are working against powerful elements of human nature. If a “good story” trumps the facts much of the time with many people, we are in deep trouble.

From David Martosko, Director of Research for the Center for Consumer Freedom:

Want propaganda with your tuna?

I consider myself an open-minded person. So just because a writer decides to take an unwarranted pot-shot at the nonprofit group I represent, just because she exemplifies the woeful state of what passes for science journalism, just because she relies on Internet gossip to try and discredit my work, just because she seems blissfully unaware of the public-health damage she’s doing, do I dismiss her too-clever-by-half attempt to put a skull and crossbones on fish, and anyone who dares to defend it?

Of course not.

I consider myself an open-minded person. So just because a group attacks drunk-driving laws and anti-smoking regulations, just because it opposes replacing the junk food in school cafeterias and vending machines with healthy snacks, just because it opposed reducing the blood-alcohol level that constitutes the legal definition of drunk, and just because it calls concerns about obesity “hype,” do I dismiss its defense of mercury in tuna fish?

Of course not.

So when the Center for Consumer Freedom sent me (and probably scores of other reporters) a press release slamming yesterday’s New York Times story chronicling the high mercury levels the newspaper found in tuna sushi served in New York City restaurants and sold in upscale stores, I didn’t reflexively think, “oh, this is the group jump-started with a pile of money from a tobacco giant.” I didn’t think, “this is the group whose leader promised said tobacco company, Philip Morris, ‘to unite the restaurant and hospitality industries in a campaign to defend their consumers and marketing programs against attacks from anti-smoking, anti-drinking, anti-meat, etc. activists.’” I didn’t automatically recall the Washington Post editorial citing “documents showing that Coca-Cola, Wendy's, Tyson Foods, Cargill and Outback Steakhouse are among [founder Rick] Berman's largest donors.” I didn’t automatically recall that Berman had, as the Post reported, “accused Mothers Against Drunk Driving a. . . of ‘junk science, intimidation tactics, and even threats of violence to push their radical agenda.’” (I found those references only later.)

Think of one word that can form a compound word with “sauce,” “pine” and “crab.”

I’ll wait . . . .

Time’s up: did you come up with “apple,” to make “applesauce,” “pineapple” and “crabapple”? OK, let’s consider that a warmup. Try the same exercise—finding a word to make a compound word—with “bump,” “step” and “egg.”

Did “goose” pop into your head?

One more: for “back” “clip” and “wall.” . . . .It’s “paper,” for “paperback,” “paperclip” and “wallpaper.”

If you’re like many people, you tried to solve each problem methodically, first finding a word that would go with, say, “sauce” and then trying it out with “pine” and “crab.” But if you’re like most people in a more important way, if you solved these brain-teasers you did so not through this grind-through-the-possibilities approach, but through insight. That is, you thought a little and then, wham, the answer suddenly hit you.

Scientists have approximately no idea how this happens.

Don’t say we didn’t warn you. Anyone, especially in the northeast and Midwest, who is surprised by the arctic express that moved in over the weekend and is still gripping most of us today wasn’t paying attention last month when climate scientist Judah Cohen issued his detailed winter forecast, the subject of my column in the December 17 issue of NEWSWEEK.

Unlike the official forecasters at the National Weather Service and elsewhere, Cohen, director of seasonal forecasting for Atmospheric and Environmental Research, Inc., doesn’t base his prognostications on crude indicators such as the status of El Nino. His research shows that something much subtler—the amount of snow cover in Siberia around the end of October—is the best crystal ball ever discovered when it comes to predicting winter weather in the U.S.

The connection, as I explained in the column, has several steps. But when Cohen ran the data through his forecasting model he came up with a prediction for cold for about the first three weeks in December, followed by milder weather especially during the first half of January (for which my heating bill thanks you) and a return to cold around Martin Luther King, Jr.’s birthday. Yesterday’s Giant-Packers playoff game was one of the coldest in NFL history. As Cohen writes me, “To predict swings in the weather almost to the day two months in advance should be impossible based on accepted climate theory. After all, chaos theory was invented to explain climate dynamics.”

Dumb luck? Doubtful. Will the rest of Cohen’s winter forecast, as well as those in coming years, prove as accurate? His track record is impressive, beating the official forecasts numerous times, but only time will tell. Will government forecasters acknowledge that Siberian snow cover can be a useful forecasting tool? When I spoke to them last month they were politely dismissive. But it’s tough to argue with success after success.

Here in science-writing land, when it comes to biomedicine we try hard to stick to rigorous, vetted evidence. That means studies published in reputable journals by, ideally, scientists with no financial or ideological stakes in what they’re investigating. Testimonials and anecdotal reports of patients who swear by some new remedy don’t count (except when we need a “real person” to liven up a dry medicine story).

So you can almost hear science writers emitting a loud collective groan this evening. It turns out that doctors and other researchers have been a trifle, well, selective in which studies they publish on antidepressants.

This conclusion emerged when scientists led by Erick Turner of Oregon Health & Science University and the Portland Veterans Affairs Medical Center compared studies in medical journals to studies submitted to the Food and Drug Administration. The difference? When a manufacturer asks FDA to approve a new drug, it has to submit all studies on the drug's safety and efficacy. But no such law compels anyone to publish those studies where you and I can read them.

Lo and behold, when Turner and his colleagues compared the two batches of studies—the uncensored whole, in FDA’s files, vs. the selected-for-publication subset—on 12 widely-prescribed antidepressants approved between 1981 and 2004, involving 12,564 patients, the mismatch was jarring, they report this evening in the New England Journal of Medicine. In the published literature, 94 percent of the studies concluded that the antidepressant worked better than a sugar pill. In the FDA files, 51 percent of the studies were positive. Of 36 studies that were not positive, 33 either were not published or were spun in such a way as to seem positive.

Turner put it this way in a statement: “Selective publication can lead doctors and patients to believe drugs are more effective than they really are, which can influence prescribing decisions." Based on all the studies and not the cherry-picked ones, each antidepressant was less effective than the published literature made it seem—and that stories in Newsweek and everywhere else that rely on that published literature conveyed.

It isn’t clear, says Turner, whether negative studies get deep-sixed because of the file-drawer effect (authors and sponsors don’t bother to submit manuscripts, for reasons I’ll let you infer), or because journal editors and reviewers decline to publish the negative studies that they do receive. I think he’s being too kind. With the proliferation of journals, virtually anything can get published somewhere—maybe not in the NEJM, but in some third-tier rag, which would still count as “published.”

The result of this selective publication is no less than a distortion of science and—since these are studies that drive what doctors advise their patients to do and what patients ask for—a perversion of the biomedical system in which untainted results are supposed to benefit public health. As Turner said, “doctors and patients must have access to evidence that is complete and unbiased when they are weighing the risks and benefits of treatment.” As things now stand, they do not. So next time you read or hear a story in the media about the wonders of a new drug, stop a minute and ask which contrary evidence might be moldering in a file drawer somewhere.

Although the Europeans got silver, gold, converts and tobacco out of their conquest of the New World in the 1500s, the Native Americans got nothing but genocide, as what UCLA biologist Jared Diamond called “guns, germs and steel” killed an estimated 90 to 95 percent of the Native Americans—a horrifying 20 million souls. Nothing was more one-sided than the direction that germs traveled. European conquistadors thoughtfully introduced smallpox, influenza and measles, against which the populations of the Americas had no immunity. Result: disease killed more of them than guns or steel.

Only one disease, scholars have long suspected, might have made the trip east to Europe: syphilis. Circumstantial evidence supported an America-to-Europe trajectory: the first recorded epidemic of syphilis occurred in Europe in 1495, upon Columbus’s return. Although some medical historians have argued that the syphilis pathogen (the bacterium Treponema pallidum) existed in Renaissance Europe long before Columbus returned from his voyage to the New World, the most sophisticated study to date, being published today in the journal PLoS Neglected Tropical Diseases, concludes otherwise: a genetic analysis of the treponeme bacteria supports the “Columbian theory” of syphilis’s origins in the Americas. Call it Montezuma’s revenge, squared.

To trace the origins of syphilis, scientists have mostly studied old bones, which preserve evidence of late-stage syphilis. But because it is tough to pinpoint the exact age of the bones, these studies have been inconclusive. Kristin Harper of Emory University and colleagues therefore studied 21 genetic regions in the genomes of 26 geographically disparate strains of treponemes. Based on how much the different strains had diverged from the basic genetic blueprint, the scientists were able to create a family tree for treponemes. It showed that the strains that cause venereal syphilis originated most recently. Their closest relatives were strains collected in South America that cause the disease yaws. Together, they say, the analyses supports the idea that syphilis originated in the Americas.

But wait. The syphilis that was present in the Americas when Columbus landed (there was a treponemal infection in the Dominican Republic when he arrived) might not have been venereal—that is, spread sexually. “Therefore, it is not clear whether venereal syphilis existed in the New World prior to Columbus’s arrival,” write the scientists. “While it is possible that Columbus and his crew imported venereal syphilis from the New World to Europe, it is also possible that the explorers imported a non-venereal progenitor that rapidly evolved into the pathogen we know today only after it was introduced into the Old World.” If so, then the Americas provided the ancestral germ, but that germ assumed its deadly venereal form only after it became ensconced in Europe.

Critics of the new study say the analysis compared too few DNA sites to reach the conclusions it did, arguing that “no evolutionary order” for the syphilis family of bacteria can be inferred, and urging “caution” in accepting Harper’s claim. Still, this study, combined with earlier work, presents the strongest evidence that the Native Americans got at least a modicum of revenge on their killers.

At a time of looming recession, soaring federal budget deficits and a wave of home foreclosures, probably the last group we need to feel sorry for (on economic grounds) is high-energy physicists. But think again.

Last August President Bush signed, with great fanfare, the “America Competes Act”. Among other provisions, the law “supported” (a key word we will return to) doubling federal support for basic research in the physical sciences, and made bold promises about improving math and science education so the U.S. could hold its own against the growing sci/tech juggernaut from Chins and India. That was then.

Despite the widespread myth that snakes (lacking outer ears, a tympanic membrane and other evidence organs of audition) cannot hear, it seems we have been too dismissive about these reptiles’ sensory abilities.

According to physicists Paul Friedel and J. Leo van Hemmen of the Technical University in Munich and Bruce Young of Washburn University in Kansas, however, not only can snakes hear. They can hear in stereo. Through their jaws.

Snakes’ jaws are connected to an inner ear with functional cochlea. Resting on the ground, a snake’s jaw can detect tiny vibrations that act like sound waves, the physicists will report in an upcoming issue of Physical Review Letters. As a result, the footsteps of, say, a mouse—to say nothing of the footsteps of a person—cause surface waves to propagate in the ground, which the snake detects as sound and “should be regarded as significant sensory input,” conclude the scientists.

They carried out a geometric study of the anatomy of desert horned vipers and the ground waves created by the footsteps of their prey. The jaw-to-cochlea system, it turns out, is attuned to the frequencies of the prey’s ground vibrations. Worse (for anyone or anything planning to tiptoe past a snake), snakes’ ability to unhinge their jaws and swallow their prey whole means the right and left jaws can receive vibrations independently. In other words, snakes hear in stereo, and so can use the auditory information to pinpoint the locations of passers-by.

You didn’t really think the stem-cell wars were over, did you?

When two groups of scientists independently reported that they had caused adult human cells to regress to a state that seemed indistinguishable from embryonic stem cells, it seemed the long and bitter battle over stem cells might be history. Rather than needing days-old human embryos to supply “pluripotent” stem cells—so-called because the cells have the ability to develop into any of the 200-plus kinds that humans have, from liver and neuronal to skin and muscle—scientists could simply take a skin cell, insert four turn-back-the-calendar genes, and presto: embryonic-like stem cells. Or, as scientists call them, reprogrammed or induced stem cells. No more need for embryos, such as those being thrown out by fertility clinics, as the source of stem cells.

Not so fast. Other scientists are still going full speed ahead in the quest to use stem cells from human embryos. Says biologist Robert Lanza, chief scientific officer of the biotech company Advanced Cell Technology, “we still don’t know if the reprogrammed cells are going to be able to do all the same things as embryo-derived stem cells. For instance, they may make neurons but not insulin-producing cells. Or even if they do, they may not do it as well. Until we have these answers, we cannot afford to abandon any lines of research.”

But like every scientist I know in the field, he is sensitive to the ethical concerns raised by destroying even 16-cell human embryos to derive stem cells. Today he and colleagues are describing the first-ever creation of human embryonic stem cell lines created without destroying any embryos, something scientists have struggled to accomplish for years.

“This is a working technology that exists here and now,” says Lanza, in contrast to the years of research that is probably needed before reprogrammed cells can be used either as treatments for diseases or for basic research. “It could be used to increase the number of stem cell lines available to federal researchers immediately. We could send these cells out to researchers tomorrow. If the White House approves this new methodology, researchers could effectively double or triple the number of stem cell lines available within a few months. Too many needless deaths continue to occur while this research is being held up.” He is referring to President Bush's August 2001 decision that no scientists receiving federal support can use any stem cell lines other than the few that were in existence at the time of Bush's announcement.

By a widely-cited count, 3,000 Americans die everyday from diseases that could benefit from stem cells.

To create batches of embryonic stem cells without destroying the embryos they came from, Lanza’s team removed a single cell from an embryo, they report in the journal Cell Stem Cells. That’s what physicians at fertility clinics do to carry out pre-implantation genetic diagnosis. As with PGD embryos, thousands of whom have been born, the embryos missing one cell didn’t seem to mind: just over 80 percent, comparable to the rate achieved with PGD, continued to develop normally (and were frozen).

Meanwhile, the removed stem cells were grown in lab dishes with special nutrients. “The stem cells were genetically normal,” says Lanza, and differentiated into a wide variety of cells, “including insulin-producing cells, blood cells, neurons, beating heart cells, cartilage, and other cell types of therapeutic importance.”

Lanza has been laboring in the stem-cell trenches for years, and is passionate about the need to reduce obstacles to the research. “There is an urgent health crisis out there, and we cannot afford to hold this research up any longer,” he told me by email. “Anything we learn from these ‘real’ embryonic stem cell lines--say, how to generate vital cell types to treat patients--can also be applied to [reprogrammed] stem cells once the technology is safe enough to use clinically. No time will be lost while we wait. The problem is that there are only a few old NIH-approved lines that researchers who receive federal funding are allowed to use. Many of these are poor quality, sick, and have started to display genetic abnormalities. These new lines are robust and can generate cell types far better.”

Advanced Cell has reportedly been told by a White House official that, once their paper has been published, the administration will make a decision on whether this new source of human stem cells passes ethical muster. Stay tuned. Lanza, for one, says, "it makes me sick to think how much time has lost."

Remember the diaper wars of the 1980s? If your memory goes back that far, you may recall the battle over whether cloth diapers or disposables were worse for the environment. Most people assumed that Huggies and the like were eco-villains because they caused so much solid waste and were made with petroleum-based plastic. But Pampers partisans pointed out that cloth diapers require loads of hot water to wash (using fossil fuels and thus causing emissions of greenhouse gases) and loads of gasoline to pick up and deliver to the households using a diaper service. At the end of the day, it was basically a draw, coming down to whether you viewed landfills or global warming as a worse problem.

The current war over biofuels, such as ethanol from corn and sugarcane, has the same flavor. Boosters call biofuels eco-saviors; detractors say they will eat up vast amounts of farmland and natural habitats, not to mention drive up food prices (as the burgeoning use of corn for ethanol has in the U.S.) and yield almost no reductions in greenhouse-gas emissions anyway. But as Jörn P. W. Scharlemann and William F. Laurance of the Smithsonian Tropical Research Institute in Panama note in the current issue of Science, whether biofuels are a net good or a net evil depends on what aspects of the environment you care about.

Compared to petroleum, they note, “nearly all biofuels diminish greenhouse-gas emissions.” But switchgrass is a much better feedstock than corn or soy, and the exact greenhouse balance sheet depends on local growing conditions (are you going to use a lot of petroleum-based fertilizer?). More central, they argue, the “focus on greenhouse gases and energy use is too narrow. The arguments that support one biofuel crop over another can easily change when one considers their full environmental effects.”

For instance, sugarcane such as that used in Brazil to make ethanol doesn’t look as green if, to grow it, you raze carbon-rich tropical forests to make the sugarcane fields, causing vast greenhouse-gas emissions. And if you care about not only greenhouse emissions but also about biodiversity and soil protection, then turning jungles into sugarcane fields looks even worse. And are you planning to use nitrogen fertilizers, as corn and rapeseed require? In that case, you’ll be emitting a lot of nitrous oxide, a greenhouse gas that also destroys stratospheric ozone.

A study done for the Swiss government and summarized by Scharlemann and Laurance compared gasoline, diesel, and natural gas with 26 biofuels, assessing the total environmental impact of each. Of the 26, 21 reduce greenhouse-gas emissions by more than 30 percent relative to gasoline. But 12 of 26—including corn ethanol, Brazilian sugarcane ethanol and soy diesel, and Malaysian palm-oil diesel—have worse environmental impacts than fossil fuels. The best biofuels are produced from organic material that isn’t specially grown for that purpose, such as biowaste or recycled cooking oil, or ethanol from grass or wood.

Things get even more complicated if you factor in things like U.S. government subsidies for corn-based ethanol production. That is making many American farmers shift from soy to corn, which in turn is driving up global soy prices. Result: greater incentives to destroy the Amazon rainforest and Brazilian tropical savannas for soy farms. “Multibillion-dollar subsidies for U.S. corn production appear to be a perverse incentive from a rational cost-benefit perspective,” conclude the scientists. But then, who ever said U.S. environmental policy was rational?

All in all, a welcome reminder that weighing enviro-costs and benefits of biofuels is no easier than the diaper decision.

The mark of a scientist is being able to change his or her mind in light of new evidence, but when the online intellectual salon edge.org chose as its annual question, “what have you changed your mind about? why?,” I confess I didn’t have very high hopes for what the biologists, physicists and other scientists who post to the site would come up with.

In my line of work, if you are looking for a scientist who can argue the merits of genetically-modified crops, the details of human evolution or any other question, it is as rare as hens’ teeth to hear that the position the scientist currently holds is not the one he or she held in the past. Members of the species Homo scientificus just don’t change their individual minds (though the community does; that’s what we call scientific revolutions, as per Thomas Kuhn. Something to do with being identified with, and having an intellectual stake in, a certain position, I guess.

So it was refreshing that of the 119 (as I write this on New Year’s Eve day) scientists weighing in on edge.org, at least half a dozen had surprisingly humble, refreshing new thoughts on long-entrenched positions. You can read the scores of answers yourself (though I do not recommend it as a hangover cure), but these are my favorites: