By calculating genetic distance, and using rate of change from molecular clock, researchers can estimate when two lineages diverged

It is true that by calculating genetic distance, and using rate of change from molecular clock, researchers can estimate when two lineages diverged.

To add, genetic distance is the term used to describe the number of differences or mutations between two sets of Y-chromosome DNA or mitochondrial DNA test results. Having zero genetic distance equates to having an exact match and that there’s no differences in the two results presented. A lot of people mistakenly assume that genetic distance is the number of generations to a common ancestor, but that is NOT AT ALL what genetic distance means. Genetic distance can also be identified by how many a particular match’s mutation difference to the participant.

"1. it should be, it has been for about 20 years, and it's really not much different in the end than breeding animals to have particular traits. there are always concerns about genetically engineered animals/plants affecting the environment in unexpected negative ways, but i can't think of an example where the fears didn't turn out to be baseless.  

first, as you point out, it would be a great advance in pharmacology, to be able to tailor drugs and their doses to me. the pros involve better medical treatment. the cons involve privacy issues like insurance companies denying coverage to people with genetic risk factors. looking at dna markers wouldn't affect the frequency of genetic diseases, but it would allow detection of them earlier. and ok, actually i suppose that if people used this information to avoid having children with genetic diseases, some might decrease in frequency."