The Hardy-Weinberg principle is not generally found in nature because it requires certain conditions in an environment. These conditions are the absence of the things that can cause evolution. In other words, if no mechanisms of evolution are acting on a population, evolution will not occur--the gene pool frequencies will remain unchanged.
Some pregnant women experience a metallic taste in their mouth during the early stages of pregnancy, because of the hormone changes. It's also fairly common to crave certain foods, or go off certain foods, and have a heightened sense of smell.
Among the drugs that can cause a metallic or coppery taste in your mouth are antibiotics like Biaxin (clarithromycin); Flagyl (metronidazole) , used to treat a wide variety of infections; drugs used to treat an overactive thyroid; captopril, used to treat high blood pressure ; griseofulvin, used to treat skin infections; lithium, used in bipolar ...