Who needs toxins in baby's milk? Certainly not baby! Unfortunately, many children are being exposed to toxins like BPA and phthalates through their bottles and sippy cups. BPA, or Bisphenol-A, is a material used in most common plastics. It mimics the human hormone estradiol, and even the FDA has said they have “some concern about the potential effects of BPA on the brain, behavior and prostate gland of fetuses, infants and children.” (FDA quotation taken from this Dr. Mercola article.)
With this in mind, it's not a very difficult decision to switch to glass for baby's bottles. And the good news is, it's not very hard, either! I love Evenflo's Classic Glass Bottles, and have used them with both Nathaniel and Micah. They're super durable, fit perfectly with my Medela electric pump, and you can buy them anywhere- Walmart, Amazon, etc... They come in 4 oz. or 8 oz. bottles, and are absolutely adorable! They feel like bottles for dolls, they are so sparkly and small. Plastic bottles just don't sparkle.
For other children's feeding products that are BPA and phthalate free, I'd recommend this awesome online store, which is actually owned by my neighbor's sister! It is called The Soft Landing.
For more on the issue of BPA and plastic safety, see this Dr. Mercola article.