Science has shown that approximately 1 in 20,000 men have no Y chromosome but instead have two X chromosomes and women can have XY chromosomes instead of the traditional XX, which means human sex determination is not just a product of the chromosomes X and Y, but rather a product of our total genetic makeup in both the brain and behavior.
A 2019 Study describes how xenoestrogens, bisphenol A (BPA) and bisphenol S (BPS), can alter a developing fetus's sex specific regions in the brain, as well as changes in reproductive organs, both of which can lead to reproductive health concerns in adulthood.
A recent study discovered exposure to bisphenol A (BPA) caused sexual dimorphism and estrogenization which may explain the increased incidence of various metabolic disorders.
An increasing number of children in our modern world are born intersex (ambiguous genitalia/hermaphrodite, pseudohermaphroditism, etc.) which studies are linking to endocrine disrupting chemicals (EDCs) exposure, like bisphenol A, phthalates and dioxins.