A simple example: infertility treatments.
http://books.apa.org/books.cfm?id=431712A
http://www.springer.com/statistics/social/book/978-0-387-949...
The simple empirical fact is that human ingenuity and shared cultural knowledge is improving the human condition faster than any process of natural selection of genes could, and we can all join in on that, whatever genes we have. And it won't be too long before we can start manipulating the genes of our descendants, if we so choose.
And I don't mean that in some crazy pseudo science way.
Consider the human brain. Did you know human infants fall intellectually behind chimpanzees of the same age.
Eventually humans overtake but it's several years late, how come?
It's because our brains are so huge that we can be born without them getting all mashed up. Our skull plates are flexible and they do to a newborn's brain what would instantly kill an adult.
But our brains are adapted to deal with that, we survive and fully recover, catch up to and surpass other great apes.
But birth is STILL problematic for us humans, so we invented cesarean section.
A medical procedure which was already common by the time Cesar was born.
And ever since all the knowledge society can come up with influences who survives.
This kind of group level evolution is not unique to us, a lot of social animals have aspects of that But we're unique in just how much our intellectual innovation matters.
Short answer, we're selecting for brains and not much else. And that's a good thing.
Chimpanzee's have a much better immune system then us, but they're endangered.
In general, I think the question is 'yes'. Because all humans can "connect" with all other humans in society, it doesn't leave pockets of evolution to take hold.
I suspect that in the next few hundred years, as real space journeys become normal, that we may see evolution start to do it's thing again.
"Survival of the fittest" is a useless tautology. An organism's evolutionary fitness, if there were such a thing, would be its ability to survive to reproductive age. So of course the fittest survive, we've defined fitness to mean survival.
In reality it's the species that has an evolutionary fitness; and the distinction is important. Take a bee colony for example, a huge number of the bees are infertile.
To address your example: infertility treatments may catalyze an evolutionary process of selecting against those who are disinterested in child rearing. Or, like the bee colony, infertility in some members of the species may be evolutionarily advantageous; hard to imagine, but not without precedent.
Sorry but no. Read "The Selfish Gene" by Richard Dawkins. Selection does NOT act on the level of a bee colony, it acts on the level of the individual genes to be found within that colony. So sure some bees are infertile, but they are in service of the genes of the fertile bees. They are in effect enslaved by the genes of the Queen bee for instance.
Some types of ants will raid the colonies of other ants, and kidnap their children, bring them back, and the kidnapped children were grow up in service/servitude to the colony which had kidnapped them, and join in on future raids of what was once their home nest. The kidnapped ants are in service to their captors, to the genes of their captors. Say for instance the kidnapped ants were black, and their captors were red(or the other way around), so, even though the kidnapped ants do not have the "red" gene, they are helping to promote the selective advantage of the "red" gene by joining in the hunt for the colony of their captors. It is not a matter of "colony a" being selected for over and above "colony b". It is rather the genes of either colony getting selected for over other genes. All life, from viral to the naked apes like us, are subject to "the tyranny of the selfish gene".
What Dawkins is likely saying (I haven't read the book), is that we can (or even should) forget about individuals and just look at relative gene frequencies (b/w generations); we'll see that some are selected for and some are selected against. And that this is actually the level at which evolution occurs.
For example, if evolution were to have its way, HIV should kill off those humans who lack the CCR5 gene. This would be bad news for most Africans and Asians, as well as up to 95% of people of European descent.
The deletion mutation of CCR5 in Europeans is possibly an evolutionary adaptation to mediaeval European plagues - the Black Death and smallpox. (see http://en.wikipedia.org/wiki/CCR5 )
We don't have a moral obligation to evolve. I'll stick with medicine, personally. As well as clothes, houses, electricity, supermarkets, central heating and air conditioning.
http://video.google.com/videoplay?docid=1597642154209383351 (naughty language warning).
I don't take that on faith. Rather, it's my prediction based on all the historical and scientific data and analysis we've accumulated.
What gives me some hope for our current circumstances and our own species, is that so far, as education and affluence rise, birth rates drop. If we can use this to mitigate the pressure of increasing population against dwindling resources (including the health of ecosystems), perhaps we can reach a sustainable existence with regard to the earth and its ecosystems. Our species' evolution will continue, but hopefully in a sustainable fashion.
Life has shown itself to be very pervasive, at least on this planet. If we fill the world up with radiation, heavy metals, organic toxins, and whatnot, some forms of life will adapt to cope. But I'd prefer that there not be such a large set back. Not another "great extinction". Life on the planet has reached an interesting level of complexity. I'd rather see that continue on without interruption. But then again, that is merely my subjective preference.