A recent study may have found evidence that suggest pollution exposure of all things may influence the sex of a pregnant woman's child. The research team was able to link exposure of pollutants like iron, lead, mercury, carbon monoxide, aluminum and polychlorinated biphenyls in the air to altering the sex of an unborn child. Some water pollutants like chromium and arsenic were also discovered. While the pollutants aren't directly changing the sex of the child, they are adversely affecting survival rates of human embryos, and the nature of the pollutants actually favor harming one sex over the other. In other words unborn females may be resistant to some pollutants that kill off the males and vice versa.