Phytoestrogens, especially from soy, are the major dietary source of estrogenicity... Furthermore, we found soy lecithin to be strongly estrogenic.

After adjustment for potential confounders including age, education, marital status, current smoking status, a history of chronic diseases and exposure to other chemicals, and employment history, the BPA-exposed workers had a significantly higher risk
of sexual dysfunction among all indices measuring male sexual function in four domains (sexual desire, erectile function, orgasmic function and overall satisfaction with sex life), compared with the unexposed workers (Table IV). The exposed workers had a nearly 4-fold increased risk of reduced sexual desire (OR ? 3.9, 95% CI 1.8-8.6), greater than 4-fold increased risk of erection difficulty associated with BPA exposure (OR ? 4.5, 95% CI 2.1-9.8), more than 7-fold increased risk of ejaculation difficulty (OR ? 7.1, 95% CI 2.9-17.6) and almost 4-fold increased risk of reduced overall satisfaction with sex life (OR ? 3.9, 95% CI 2.3-6.6)

Animal studies have shown that BPA affects the male reproductive system including androgen receptors (ARs), male sex hormone levels, male reproductive organs including testes, epididymis, sperm and seminal vesicles, the prostate gland and sperm production (Richter et al., 2007; National Toxicology Program, 2008). Changes in sexual behavior including a reduced performance in latency and frequency of intromission among rodents that had been exposed to BPA have also been reported (Farabollini et al., 2002; Della et al., 2006; Richter et al., 2007). BPA has been shown to have both estrogenic and antiandrogenic effects in both in vivo and in vitro studies (Sohoni and Sumpter, 1998; Lee et al., 2003; Xu et al.,2005; Sun et al., 2006; Wetherill et al., 2007; National Toxicology Program, 2008). Nonetheless, some researchers have not observed any effects of BPA in their animal studies (Tyl et al., 2002; Tyl et al., 2008a, b). However, these findings of a lack of an observed BPA effect have been recently challenged by a group of scientists from more than 30 academic and research institutes (Myers et al., 2009).

Bisphenol A (BPA) may cause testosterone reduction by adversely affecting both testis and pituitary systems similar to estradiol.