Parabens

Parabens are a class of chemicals widely used as preservatives by cosmetic and pharmaceutical industries. Parabens are effective preservatives in many of formulas. These compounds, and their salts, are used primarily for their bactericidal and fungicidal properties. They can be found in shampoos, commercial moisturizers, shaving gels, personal lubricants, topical/parenteral pharmaceuticals, spray tanning solution, make up, and toothpaste. They are also used as food additives.
 
Their efficacy as preservatives, in combination with their low cost, the long history of their use, and the inefficacy of some natural alternatives like grapefruit seed extract (GSE), probably explains why parabens are so common place. They are becoming increasingly controversial, however, because they have been found in breast cancer tumors (an average of 20nano grams/g of tissue). Parabens have also displayed the ability to slightly mimic estrogen (a hormone known to play a role in the development of breast cancer). No effective direc link between paragons and cancer have been established, however, another concern is that the estrogen-mimic aspect of paragons may be a factor in the increasing of early puberty in girls. We do not support any products that contains Parabens.
Source: Wikipedia