These are the crucial questions of the whole genetic research. For instance Mozart has been diagnosed to be very likely bipolar. I think it's in the hands of people in society to not give scientists all the power, but to become actively informed and involved in a societal discourse about these matters. I m an ethicist concerning those issues. My take is that right now, the 90 percent mapping of the genome has no impact whatsoever on medical treatments because there are actually very, very few and rare diseases which are linked to one singular gene.
Most diseases are far more complex than that.
As for right now, we have no way to explain or even understand the complexity of the genetic interactions and the interactions between the genotype and the outside world. Therefore, we are not even now close to having any impact on medicine right now. My take on that is that they absolutely should. From an ethical perspective, they should. This brings us back to the question of normality and standards for that, and it also brings us back to the question of person-hood.