Concerns raised by scientists in the U.S. last month about Bisphenol A, a controversial chemical found in most plastic baby bottles has led to calls from groups in Britain for all baby bottles to be clearly labelled.
Scientists from the National Institutes of Health in the U.S., recently revealed that in 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; the chemical mimics the female hormone oestrogen.
As a result many major U.S. retailers, including Wal-Mart, are discontinuing the sale of such bottles, while Canada is after a complete ban - the Wal-Mart subsidiary in the UK ASDA is producing its own BPA-free range.
While the National Childbirth Trust says it is concerned and wants all UK bottles clearly labelled, the government insists they are safe to use.
BPA is commonly used in reusable plastic products to prevent them from shattering but there have been suspicions concerning the use of the chemical for more than a decade - but it continues to be used in the production of most plastic baby bottles.
The National Childbirth Trust has advised parents not to pour boiling water directly into a bottle, as this could cause more of the chemical to be released, and to discard scratched and damaged bottles.
The charity says 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 to remove the risk of BPA contamination.
The campaign group Chemtrust has called for BPA to be banned from all plastic products where there is a risk of leaching and says it should not be used in baby bottles.
A spokesman for the Chemical Industries Association says the use of Bisphenol A in food and drink products was passed by UK and European food standards authorities last year.
The Food Standards Agency and the manufacturers however maintain that the amount of the chemical in such products is well below levels considered harmful and the bottles are completely safe to use.