In 2003, Philippa Darbre and colleagues at the University of Reading carried out landmark tests of 20 different human breast tumours. Their results were published in the Journal of Applied Toxicology and confirmed traces of parabens in every tissue sample.

The tests suggest that parabens, which are widely used in personal care products as a preservative seeped into breast tissue after being applied to the skin.

"This is the first study to show their accumulation in human tissues," said Dr Darbre. "It demonstrates that if people are exposed to these chemicals (parabens), then the chemicals will accumulate in their bodies."

While there is currently no evidence directly linking parabens and cancer, the scientists called on authorities to review the use of parabens in personal care. The personal care industry continues to insist on the safety of parabens.