Nalgene water bottles have long been a trusty earth friendly alternative to using disposable water bottles. These virtually indestructible bottles are made of hard plastic, come in varying sizes and colors, and have long been trendy sports accessory .

Yet recently, amid concern about a hormone-mimicking chemical used in Nalgenes several retailers (including Patagonia and the Canadian Mountain Equipment Co-op) to remove Nalgene and other polycarbonate plastic containers from store shelves.

Ben Dobbin of the Boston Globe reports that "There is little dispute that the chemical can disrupt the hormonal system, but scientists differ markedly on whether very low doses found in food and beverage containers can be harmful. The US Food and Drug Administration sides with the plastics industry that BPA-based products do not pose a health risk."

A panel of researchers at a US government conference reported that the potential for BPA to affect human health is a concern, and more research is needed. The panel also noted evidence that Americans have higher levels of BPA than those found to cause harm in lab animals. Yikes.

Like all the warnings about lead in children's products that have cropped up this past year, including a recent recall of metal water bottles, it's hard for consumers--especially parent consumers who must make responsible decisions on behalf of their kids--to know what to worry about and what not to.

Many outdoor enthusiasts who have used Nalgenes for years seem unconcerned about the possible BPA hormone disruption that the Nalgene bottles may cause. Other plastic bottles may also pose the same threat. Here's how to tell if your child's watter bottle is safe.

I'm veering on the side of caution with this one. Just as hormone free milk seems like a good idea, I'm thinking that this is just one more reason to love Sigg's awesome water bottles for kids.