Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), also referred to as dioxins, and polychlorinated biphenyls (PCBs) are persistent organic pollutants (POPs). Because of their accumulation in the food chain and their possible toxicity at even environmental background concentrations, they are still of environmental concern, although exposures have markedly decreased in the general population (Wittsiepe et al. 2000). Dioxins and PCBs are mixtures of congeners that differ in the number and the position of chlorine atoms on the two ring systems. Depending on the degree of chlorination, their biological half-life varies from days to years (Ogura 2004). PCDD/Fs are by-products of combustion processes. PCBs were synthesized and used as synthetic oils in many diverse industrial applications from 1929 until their production and further use was discontinued in the late 1970s.
A broad spectrum of toxicological properties has been reported for both PCDD/Fs and PCBs including neurodevelopmental dysfunction (Schöler und Färber 2002). A more recent emphasis is on their established interference with endocrine systems, such as the hypothalamic–pituitary–thyroid (HPT) and the hypothalamic–pituitary–gonadal (HPG) axes, which also play a regulatory role in brain development (Bergman et al. 2013). Vreugdenhil et al. (2002) reported evidence suggesting that gender-related play behavior as rated by the mothers by means of the Pre-school Activities Inventory (PSAI) (Golombok and Rust 1993)was modified in an antiandrogenic and estrogenic fashion by pre-/perinatal levels of PCBs and PCDD/Fs in a cohort of 158 Dutch children. This was the first pidemiological report to suggest that endocrine disruptors (EDCs) may alter the normal sexual structuring of the brain with resulting behavioral sequelae. In a more recent study, and again using the PSAI, similar modification of sex-related behavior was reported after prenatal exposure to phthalates, another group of widespread environmental EDCs (Swan et al. 2010).