Obesogens are chemicals that are foreign to the body that can disrupt normal development or homeostasis (usually concerning metabolism and use of lipids, or fat).
Obesogens can effect the distribution of fat and sexual characteristics by disrupting genes.
For example, if an obesogen affects where fat deposits are located, it could do so by disrupting the genetic expression (by increasing or decreasing the propensity of a cell to produce certain proteins) of the biochemicals which regulate where fat is deposited. If this happened and there was more fat in the blood vessels of the heart, a heart attack could be more likely.