Terribly interesting (and frightening) article in the Feb 2009 issue of Fast Company Magazine about the chemical BPA and it's impact. The piece titled "The Real Story Behind Bisphenol A" looks at both the effects of BPA with constant exposure and how those effects are denied by the industry producing it.
In short, BPA is produced in the U.S. by five different companies and is an enormous business with the chemical serving as a core ingredient in hundreds of different products that need to be shatterproof. This plastic or plastic-like output serves as the core ingredient in everything from cell phone parts to... baby bottles. This last item in particular is where things get a bit dicey. BPA has been shown to be harmful to the reproductive system and potentially cancer causing if exposed to repeatedly... especially for those with weakened or not fully developed immune systems.
Where things cross over from bad to worse is with the narrative around BPA from the companies making it. While one purely arbitrary research study after another shows BPA to be a harmful ingredient in products, industry-funded studies proclaim that all is well. Oh yeah, the U.S. regulatory arms charged with oversight of something like this have to date decided that the industry-funded studies are the ones to go with. Despite much more stringent regulation of BPA (particularly in products used by infants) in Europe as well as Canada, it's pretty much up to consumers to try to seek out non-BPA-containing products for their kids. Those products are definitely out there, but you have to work to find them. Good times.