ESR2 and obesity due to melanocortin 4 receptor deficiency: BPA has been shown to bind and activate the two estrogen receptors ERα and ERβ [16], causing multiple adverse outcomes related to the many physiological processes that ERs influence [173]: development or progression of numerous diseases such as breast/ovarian/colorectal/prostate/endometrial cancers, osteoporosis, neurodegenerative diseases, cardiovascular disease, insulin resistance, lupus erythematosus, endometriosis, and obesity.