It's easy to envisage a brave new world of healthcare, where your genetic makeup can be interpreted in minutiae, and therapy developed that is fine-tuned to your specific needs. The genetic information would be supplemented with reference to detailed ancestral information - for those with extensive enough family trees.
I heard something in passing on the radio a few days ago, which gave that a reality check. I think the woman being interviewed was a geneticist, who had researched the relationship between genetic and genealogical information - that is, comparing DNA information with supplied family trees.
Of course, the result should be quite obvious. She couched it in terms of paternity, but it turned out that there was substantial disconnect between the two sources of information. In effect, there were too many cases where the attributed father was not the actual father. This would happen for any number of reasons, from infidelity to retro-fitting a respectable background.
I see some irony here, for the many people who, for example, would like to trace their roots back to royalty. Apart from the fact that most English people (all?) should share some royal blood if they go back far enough, red herrings would abound. On the one hand, there would be cases like my grandmother's family, where it's plausible that purported links to the Dukes of Bedford would be simply an attempt to increase cachet.
Yet on the other hand there would be the hidden stories that may reveal closer links to a royal family than expected. Hidden for as many reasons as there are players.
I would not be surprised if the information flow ended up being in the converse direction. Genetic analysis may be able to correct family trees.
In that light, there is yet hope for genealogists. However, for that level of detail I would not be holding my breath. It is unlikely to come soon.