"The reason we recommend glass bottles over plastic is that plastic bottles cannot be properly sterilized nor are they environmentally friendly! On the other hand, glass bottles can be boiled for sterilization, have high re-usage rates, and do little-to-no harm to the environment (as glass is typically able to break down without releasing any chemicals). However, if you have children or are clumsy and don't like the idea of using glass in the shower, you can opt for plastic instead." However, if you have children or are clumsy and don't like the idea of using glass in the shower, you can opt for plastic instead.