I personally didn’t choose glass baby bottles for my 2 children (ages 1 & 2) but I would definitely reconsider if I was to have a third baby and this is why:
Many of the older plastic baby bottles are made with polycarbonate plastic which is a hard, unbreakable plastic and can leak a compound called BPA (bisphenol A). BPA can result in developmental hormonal complications because of the way it imitates Estrogen in our body’s.
Fortunately you can find PBA-free plastic bottles nowadays but bear in mind that plastic is also less durable than glass baby bottles and they should NEVER be put in the microwave. Furthermore, you should dispose of your plastic baby bottle as soon as it becomes at all damaged, scratched etc.
Glass is easier to clean and simply sterilised in boiling water without running the risk of leaching harmful substances into the milk.
Glass baby bottles don’t change the flavour of the milk when heated whereas plastic bottles tend to impart various flavours into the milk (including breastmilk) when heated.
Of course glass bottles do have the obvious drawbacks of being heavier as well as being breakable. Just make sure you choose a glass bottle that has tempered glass and is ‘shock resistant’. Finally, choose a glass baby bottle brand that offers silicon cover accessories.