While evolution is a constant process, the term "survival of the fittest" no longer really applies.
Today people who are born with genetic defects, through medicine, live, for the most part, perfectly normal lives. A hundred years ago people who were born with such diseases or disorders would not usually live long enough to be able to reproduce. Of course some would either through luck or simply because their disease is not fatal.
At this point, genetic diseases are incurable, while some can be managed through drugs the disease its self is still there. The only way that these diseases spread is through reproduction, and a hundred years ago the people with these diseases, like i said before usually were not able to reproduce.
But now, the people with these diseases, like huntingtons or parkinsons, have a much higher chance of living long enough to reproduce.
Hemophilia, for example, is a highly deadly disease. Before modern medicine few who had it lived. Now it is manageable to the point of the person almost being normal. Darwinism is no longer taking effect because those who would naturally die out, stopping or at least slowing the spread of "bad genes", are instead spreading the disease, effectively making the process in which evolution occurs a harmfull rather than beneficial process.
This is something that scientists should be looking into.
While it is no where near an imminent problem, it could prove to be drastic in the far future yielding to larger portions of the population only being kept alive by drugs, of course thats an extreme but also a possibility.
In light of this isn't anything we do with it still part of evolution. Saying evolution has been disrupted suggests some predefined path evolution must take, which is not how evolution works. Random mutations happen and when they have survival value they are propagated. Since acquiring reason from these mutations I would say we have done a pretty good job of surviving so our evolution has not been disrupted.
Evolution doesn't actually have anything to do with whether or not groups of organisms 'advance' or 'adapt'. That's natural selection. *Any* long term genetic shift that results in a change in overall genotype and/or phenotype is 'evolution'. This still occurs even if natural selection is not a(n) (very; it still occurs among humans) active factor to select for 'beneficial' genetic mutations. The only way to stop that from occurring is to prevent sexual reproduction, which results in new genetic formations within a given species, and to prevent any and all genetic shift within pre-existing organisms, which would require both a ridiculously totalitarian government, and extremely advanced nanotechnology. Put simply, it will never be the case that an organic species exists and evolution does not occur.
This in direct response to dangeresque, evolution is not concerned with whether people live or not. Evolution is concerned with whether people have babies or not. The more subtle diseases might make it through, but most people try not to associate (that cancer patient everyone's eyes uncomfortably slide off), much less have sex with a person who is noticeably in bad health. In addition, evolution even goes down to the sperm level. Not just that the sperm has to be able to out compete its fellow sperm and invade the defenses of the mother (there are a lot, the reason why so many good soldiers die), but also smaller less noticeable things. I recently learned from the book Genome (a lot but for simplicities sake) two things. The first is that at least some of the fluid in sperm is engineered to make the woman it impregnated more attached to whoever gave her that sperm (among other things I don't remember). If these chemicals are allowed to evolve without the woman's defense of them also evolving, they can be strong enough to kill her (granted this is in fruit flies). The second thing is that because the X-chromosome has three time the representation in the human species than the Y-chromosome it is much more dominant. The X-chromosome actively works to destroy the Y-chromosome, or in less drastic cases make better copies than it. This has happened in a species of butterfly that now only has a 2% population of males (the ones with a version of the Y-chromosome resistant to the new X-chromosomes effects). This is also the reason why the Y-chromosome is so small...Though I don't remember the science of that one off the top of my head...Really need to finish Genome. Anyway, the point is that evolution still occurs among humans, it just isn't as much of a race anymore or as obvious.