Earlier this week, the Today Show did a segment on a topic that is beginning to get a lot of attention: the safety of reusable plastic bottles. Concerns about the chemical Bisphenol A (BPA), which is found in many plastic bottles, has led the government to conduct a large-scale study that will be released within the next few weeks.

Previous studies have shown that BPA mimics hormones in our bodies and has been linked to abnormalities in the mammary and prostrate glands as well as the eggs of laboratory animals. Other animal testing has shown that Bisphenol A can cause the early onset of puberty, contribute to weight gain and lead to breast and prostate cancer.

So, the question isn't whether or not BPA is in some of our plastic bottles - it is. What hasn't been determined is just how much BPA can we ingest without adverse affects. And here is where the expert opinions become confusing. Some say the BPA levels we are exposed to from plastic bottles are too low to be of any concern. Others believe that even low levels can have neural and behavioral effects in fetuses and children.

Dr. Leo Trasand of Mount Sinai School of Medicine, thinks any exposure at all is too much. "Unfortunately, there is no level of exposure that has been identified as being safe," he says. And if that doesn't concern you just a little bit, consider the fact that a CDC study found BPA in the urine of 95% of the adults sampled, in the blood of pregnant women, in umbilical cord blood and placentas - all at levels that have been shown to alter development in animals.

So, how do you minimize your risk? Dr. Trasand says to turn your bottle over and look for a number stamped on the bottom. Number 1 bottles are commonly used for sodas and water and are considered safe for single use. Dr. Trasand says that bottles stamped with 3, 6 or 7 "are not safe for use across the board" and should be avoided.

For BPA-free options for babies and kids, check out Bethany Sanders' post on the subject.