There is no proven link between gt;breast cancergt; and household products, whether they be soap or water bottles. But many consumers, activists, and experts are concerned that a variety of goods contain gt;hormone disruptorsgt;, chemicals that when absorbed into the body can mimic or interfere with hormones such as estrogen. Some researchers believe that chemicals with estrogenic characteristics can cause normal breast cells to divide. gt;gt;"Each time they divide, they have the risk of copying DNA incorrectly and creating mutations in key genes, which may lead to increased breast cancer risk," says Suzanne Snedeker, PhD, the associate director for translational research for the gt;Program on Breast Cancer and Environmental Risk Factorsgt; at Cornell University. Chemicals that mimic estrogen might also enable an existing breast tumor to keep growing, because most tumors depend on estrogen to grow. gt;gt;Individual products contain only small amounts of these questionable chemicals, if they do at all. But there is growing concern that the ubiquity of such agents in gt;cosmeticsgt;, household products, and certain plastics, may have a cumulative estrogenic effect. "We are not saying if you use a certain product with estrogenic ingredients it will cause breast cancer," Snedeker says. "But the science suggests your risk may be reduced if you avoid these ingredients." Here are a few ways to play it safe.gt;gt;gt;View the slideshowgt;