The story. In December 2010 Felisa Wolfe-Simon et al published a paper in Science saying that they had found a form of life on Earth that used arsenic in place of phosphorus in some molecules, notably in DNA. This created a storm of protest, for many reasons. Chemists said that arsenic-containing DNA (of the sort Wolfe-Simon et al claimed) was unstable when dissolved in water. It just would not happen. Biochemists and microbiologists were more inclined to believe the basic idea, but throught that the evidence presented for arsenic-DNA fell far short of proof. In May 2011 Science published some of these objections (notably the original paper remains free for anyone to download, the objections and commentary need a subscription to read).
My take. Since the end of 2010 many scientists have done much more extensive testing on GFAJ-1, and concluded that its DNA does not contain any significant amounts of arsenic, and that it cannot grow on really pure arsenic. They have also sequenced the bug's genome, and found it to be fairly unremarkable. So GFAJ-1 is definitely not an example of 'weird life'.
The open question. Why did Science, one of the leading journals for publishing top quality science, not point this all out before pushing the paper onto its web site? The 'peer review' process is meant to catch weak or badly argued science before it gets into print (nowadays meaning 'on the official web site').
Our comment. Since originally posting this, I have co-authored an essay discussing how the different ideas of what scientists mean by 'evidence' and 'proof' were at least in part to blame for this story. It is not that physics is 'better' than chemistry, or worse, just different. Physicists have a different mental toolkit to chemists, and they to biologists. At best getting them to work together brings all those tools to bear on a problem that no one tool can solve. At worst, it is like trying to hammer in a screw with a wrench.