There is evidence (Rudel, Fenton, Ackerman, Euling, & Makris, 2011) to support a theory that exposure to high levels of
certain environmental contaminants, namely dioxin and other endocrine disruptors, while in utero (exposure to accumulated contaminants in your mother's body before you're
born) can predispose a woman to have insufficient breast growth
during adolescence and pregnancy, the two
times in her life her breasts should be growing.