There is no environment for them to be tested by, we aren't in a natural environment anymore.[b said:Quote[/b] (TheAlphaWolf @ Jan. 23 2005,3:37)]ok, and the frequency of diseases is controlled by the environment. If you're talking about pathogens, they're part of the environment. If you're talking about genetic disorders, those genetic disorders can't survive in this environment so their frequency is determined by the environment.[b said:Quote[/b] ]Natural selection by definition is the controlling of the frequency of alleles by the environment. The FREQUENCY is CONTROLLED by the ENVIRONMENT.