Parabens are used in approximately 98% of personal care products as preservatives. They are the cheapest way for manufacturers of these products to control the microbes that would otherwise proliferate.

There is, however, growing concern about the safety of parabens and manufacturers of raw materials are rapidly launching alternatives.

A study in 1998 by Dr Routledge et al in the UK showed that parabens mimic the hormone estrogen. The effect was shown to be stronger for the longer chain parabens like butyl and propyl paraben.

Sperm counts have fallen by half over the past 50 years and breast cancer has increased by more than 30% since 1980. These increases are almost certainly linked to estrogen mimics.
In 2004 Dr Darbre of Reading University showed that parabens were present in 24 of the 27 breast cancer tumours that she analysed.

Almost all breast tumours need estrogen to grow.

The most recent finding was by Professor Yoshikawa in September 2005. He found that methyl paraben in the presence of UV, accelerates the aging process in skin cells.
Parabens have been banned by all the major organic certifiers in the world including the US, the UK, Europe, Australia and Japan.

The industry response is that these chemicals have been cleared for use by the relevant authorities (FDA and ECC) and have been used for decades. The link between smoking and cancer took 50 years to gain public support. Health concerns raised by the parabens will hopefully be recognized sooner.