Can Exposure to Toxins Change Your DNA?

Can Exposure to Toxins Change Your DNA?
http://www.motherjones.com/blue-marble/2012/06/can-exposure-toxins-change-your-dna

"Let's face it, we're devoting enormous amounts of time and energy to minimize our exposures to toxins (think BPA, pesticides, and all the rest of the seemingly ubiquitous chemicals). But now an emerging body of research points to the disturbing possibility that such self-protective strategies might sometimes come decades, or even a century, too late.
If your great-grandmother experienced a brief toxic exposure, these studies suggest, you and your children could be at risk for reproductive illnesses and possibly other conditions. The presumed mechanism of this unfortunate inheritance is not a mutation in the DNA itself but rather changes in the biochemical on-off switches that determine whether or not specific genes get activated—a field of study known as epigenetics."