BPA or bis-phenol A is the main ingredient in polycarbonate bottles, the hard clear non-breakable kind that most baby bottles are made from. Unfortunately, some BPA leaches from the bottles during heating of the milk, new research showing 5-7 ppb. This is a trace level but still has potential health risk to an infant due to inappropriate hormone exposure. BPA is an estrogen mimic (originally developed as hormone replacement therapy for post-menopausal women) and so should be avoided, especially in early life when imbalances can be “imprinted” for a lifetime. Glass bottles is one alternative. Another is Born Free, a plastic baby bottle that is free of phthalates and BPA. 