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"Exposure to BPA may be harmful during pregnancy; this exposure may permanently affect the fetus," said Hugh S. Taylor, Ph.D., co-author of the study from Yale University School of Medicine in New Haven, Connecticut. "We need to better identify the effects of environmental contaminants on not just crude measures such as birth defects, but also their effect in causing more subtle developmental errors." Taylor and colleagues made this discovery by exposing fetal mice to BPA during pregnancy and examining gene expression and DNA in the uteruses of female fetuses. Results showed that BPA exposure permanently affected the uterus by decreasing regulation of gene expression. These epigenetic changes caused the mice to over-respond to estrogen throughout adulthood, long after the BPA exposure. This suggests that early exposure to BPA genetically "programmed" the uterus to be hyper-responsive to estrogen. Extreme estrogen sensitivity can lead to fertility problems, advanced puberty, altered mammary development and reproductive function, as well as a variety of hormone-related cancers. BPA has been widely used in plastics and other materials. Examples include use in water bottles, baby bottles, epoxy resins used to coat food cans, and dental sealants. "The BPA baby bottle scare may be only the tip of the iceberg." said Gerald Weissmann, M.D., Editor-in-Chief of The FASEB Journal. "Remember how diethylstilbestrol (DES) caused birth defects and cancers in young women whose mothers were given such hormones during pregnancy. We'd better watch out for BPA, which seems to carry similar epigenetic risks across the generations. "

The pileup was created in part because studios want to capture some of the excitement surrounding "Avatar," the James Cameron epic released in December. At $2.4 billion in global ticket sales, it is the highest-grossing film ever. In addition to the novelty or richer experience that might drive more people to see a 3-D movie, tickets to 3-D movies also cost a few dollars more. Around the time "Avatar" came out, Warner Bros. decided to convert a remake of "Clash of the Titans" from 2-D to 3-D and push its release back a week, to April 2. That will be the third 3-D movie to hit the market in a short span. DreamWorks Animation SKG Inc.'s "How to Train Your Dragon" comes out a week earlier, and The Walt Disney Co.'s "Alice in Wonderland" hits theaters March 5. And "Avatar" might still be playing in some places too. But a limited number of theaters can show these movies in 3-D, because not all theater owners have bought new digital projectors and undertaken other upgrades necessary to show movies in the format. About 3,900 to 4,000 3-D-ready screens are expected to be available in the U.S. and Canada by the end of March. Typically a movie in wide release might be shown on 3,000 to 10,000 screens in North America. In the past, a smaller number of 3-D-capable screens was adequate when one major film at a time was being released in 3-D in addition to 2-D. Each movie had a longer run, and moviegoers who wanted to see it in 3-D could pick a convenient time to go. With three out at once, each will get less exposure because some theaters with only one or two 3-D screens will have to choose which movies to show in 3-D. "One or all three are going to suffer in some way," said Patrick Corcoran, director of media and research for the National Association of Theatre Owners. "It makes it a much harder decision on exhibitors on what to keep or what to drop or what to add and probably should have been avoided."

Statistical validation of results, as Shaffer described it, simply involves testing the null hypothesis: that the pattern you detect in your data occurs at random. If you can reject the null hypothesis—and science and medicine have settled on rejecting it when there's only a five percent or less chance that it occurred at random—then you accept that your actual finding is significant. The problem now is that we're rapidly expanding our ability to do tests. Various speakers pointed to data sources as diverse as gene expression chips and the Sloan Digital Sky Survey, which provide tens of thousands of individual data points to analyze. At the same time, the growth of computing power has meant that we can ask many questions of these large data sets at once, and each one of these tests increases the prospects than an error will occur in a study; as Shaffer put it, "every decision increases your error prospects." She pointed out that dividing data into subgroups, which can often identify susceptible subpopulations, is also a decision, and increases the chances of a spurious error. Smaller populations are also more prone to random associations. In the end, Young noted, by the time you reach 61 tests, there's a 95 percent chance that you'll get a significant result at random. And, let's face it—researchers want to see a significant result, so there's a strong, unintentional bias towards trying different tests until something pops out. Young went on to describe a study, published in JAMA, that was a multiple testing train wreck: exposures to 275 chemicals were considered, 32 health outcomes were tracked, and 10 demographic variables were used as controls. That was about 8,800 different tests, and as many as 9 million ways of looking at the data once the demographics were considered.