On the off chance that I am just this once not the last of my friends to hear about something: There appears to be evidence that polycarbonate drinking bottles can leech a chemical (bisphenol A) that mimics estrogen, in quantities that may have significant health effects. As is usual with such stories, good reporting is hard to find on the 'net, but after looking at a dozen or so stories, I recommend this article. (From a college student newspaper, no less — which, upon reflection, I suppose we should expect to be among the last bastions of careful reporting.) ABC News reported in April that Walmart has pulled baby bottles containing bisphenol A, and Nalgene has announced it will phase it out.