Some companies now manufacture BPA-free baby bottles
More information should be given to parents about a controversial chemical found in most plastic baby bottles, the National Childbirth Trust has said.
American scientists last month raised concerns about Bisphenol A, or BPA, which they say could cause behavioural changes and the early onset of puberty.
Some US retailers are to stop selling the bottles, while Canada wants a ban.
The National Childbirth Trust wants all UK bottles clearly labelled, but the government says they are safe to use.
In April, the National Toxicology Program, part of the US National Institutes of Health, found that, based on animal experiments, exposure to low-levels of BPA "can cause changes in behaviour and the brain, prostate gland, mammary gland and the age at which females attain puberty".
In the US, major chain stores, including Wal-Mart - the word's largest retailer - say they are now going to stop selling bottles made with the chemical.
In the UK, Wal-Mart subsidiary Asda is producing its own BPA-free range.
BPA is widely used in reusable plastic products to prevent them from shattering.
The National Childbirth Trust wants bottles containing BPA to be clearly labelled.
Belinda Phipps, the charity's chief executive, said the lack of awareness was "concerning".
"As a first step, it is important that bottles and other items that might reach a baby's mouth are labelled in a standard and easy-to-understand way. This will help to remove the risk of Bisphenol A contamination."
The charity advised parents not to pour boiling water directly into a bottle, as this could cause more of the chemical to be released.
It also said scratched and damaged bottles should be discarded.
The Food Standards Agency and the manufacturers say the amount of the chemical in such products is well below levels considered harmful and the bottles are completely safe to use.