People seem to often ask if humans are even still evolving. This is meant to be a quick answer.
Humans are still rapidly evolving. Physically we are are extremely generalist, so we don't need a lot of physical change to adapt, though there will be some. Humans mostly adapt to change strategically, but that also involves a lot of genetic adaptation, just no so visibly.
Humans have left the ecology we are still most adapted to, the hunter-gatherer tribal ecology, when we started farming and cities. In ways, this is the biggest ecological change any species has ever attempted as a change of habit. It's not so much that the ecology changed and we had to adapt, we changed and still are changing, rapidly. This whole story is about those changes and how we can adapt, but a lot of that is strategic. Evolution is defined as a change in gene frequency, so what about in those terms? What genetic changes have humans made, are making now and likely to make in the future? Keep in mind that humans do survive based on strategic adaptation, but there are large genetic components to behavior, so the two must be considered together. We may learn a behavior that aids our survival, but it's difficult to learn any behavior that you don't have some genetic potential to support. Over time, if the behavior promotes survival, natural selection makes the genetic support for that behavior more common. When the instincts of a species are adapted to the environment they live in, natural selection no longer causes rapid genetic change like humans are now experiencing.
I think that the first thing people are asking in this question though is since the world seems less dangerous now, are we still adapting? Much of the world is still very dangerous, it's just the dangers are different. That relates to the second question commonly asked - are we evolving to be more intelligent? The answer to that is yes, but for more reasons than just the world is still quite dangerous. It used to be that if you were healthy and willing to get with the program (do what your tribe was doing), you had what you needed to survive. Now we need to be more intelligent for a number of reasons including we exist in a more complex society (the main reason for intelligence in humans) and also to deal with the more complicated tools we use. We live in a bigger world with more people, more dangers and there is far more to know. We need to be better at learning and judging than our ancestors. We need the skills of logic and reason used for Critical Thinking that allow us to understand and to know what is true. We need to know some politics, economics, history and other subjects that are just needed to understand the society we live in. It is how we survive. We need to know some sciences to understand the ecology that is our life support system. We need the knowledge our society has learned to maintain our physical health. We aren't very well adapted to the society we exist in, so it is naturally stressful and we need to learn some practical or street knowledge of psychology to protect our own mental hygiene.
Making genetic changes (or any changes) is always a dicey thing. Survival is the ultimate conservatism. Change for the sake of change is dumb and dangerous, but the world has changed and humans need to change. We will need to keep changing until we develop a new long term ecology and are fairly well adapted to it. The mark of humans though is to use learned strategies rather than genetic based instincts. Still, we need to adapt to those strategies we develop for survival and we do have some physical adaptation to do as well. We are going to have to husband our genes, but that does not mean natural selection will go away. It just means that artificial selection by humans will replace and add to what we have removed in terms of natural selection and called "human progress". We just aren't knowledgeable enough to do much genetic manipulation, but we will be. The main rule to keep in mind if you do genetic manipulation is to preserve balance. Survival, genetic and strategic, is all about balanceā¦ which is not the easy simple path and why so many ideas are silly - they lack balance which is always a complication, but is also always necessary.
Most of what I refer to as genetic change using artificial selection is about increasing the frequency of "good genes" rather than changing the balance of how humans act. Natural selection only acts by selecting against bad genes, not for good ones. It is a very blunt instrument. Nature does not insure that your children will inherit your best genes or the ones that give you what you respect about yourself the most. Artificial selection could and can select for good genes. Mostly I suggest increasing the frequency of these good genes, husbanding them. Rarely do I suggest changing the balance, but sometimes I do. Take the case of curiosity. Some people are very curious, some are much less so and most people fall in between. Curiosity is something I would suggest humans promote genetically to shift the general balance to a greater curiosity. Not a lot, but some. We tend to be very conservative. We need more inclination to be curious and to learn.
Another change we might see is that under natural circumstances, 25% of women die during childbirth due to complications related to the size of the birth canal. Now it is the sixth major cause of death for women of childbearing age. Birth of children with bigger heads is a real problem we aren't adapted to. It can also lead to birth defects. I have found no indication that some race or tribe has developed better pelvic mechanics to make birth easier. If there was one, we could spread the genes from that group to the rest of humanity naturally or artificially. We probably don't want to select for smaller heads at birth either. Big heads were one of the first of the adaptations on the path to modern humans and they are actually underdeveloped anyway. That balance cannot easily be changed. We could just select for larger pelvic bones in women, but then they would have trouble walking. The solution I would suggest is that women grow larger. In the future, women may commonly be bigger than men. It would allow them to give birth easier. (Sociobiology describes that males are larger in mammals to compete for females. Size is generally limited by resource availability. That is not likely to be the limit on future humans.)
If I review the reasons people are the various sizes and shapes they are, I suspect that in the future we will tend to be taller and thinner. Much of historic bulk was for cold resistance or for fighting. Both should be less important in the future. Many physical skills we have should develop over time, but our general shape will not need to change much for that.
The best genetic based physical improvement might be in the spinal structure. The commonest disability, in terms of Social Security Disability cases, is from back problems. That could be genetically improved by increasing the frequency (genetic evolution) of "good back genes". The majority of people have "good backs". Everyone could have them. Back problems are a case where it seems likely that de novo and even single point mutations could cause problems because it is a "recently" evolved feature of humans, as is the upright stance. Consider that an awful lot of your ancestors were selected against -died- because of problems with their backs. That is just one physical trait that represents a weakness in humans. There are others. In general, humans will be able to increase the frequency of genes for health and beauty in many ways.
In terms of biology, theoretically the best improvement would relate to improvements to the immune system, but good luck improving on what nature has created there. Our immune system has been so important all through evolution, that it is going to be hard to improve much. Attempting to would likely result in imbalances. You would likely increase arthritis, etc. if you try to make any changes there without a lot more knowledge. Maybe one day though, because we do live in an environment with far greater opportunity for disease to act. We may even have to accept trade offs. That is how it works.
In a tribal society, violence is a pretty good strategy. It peaked with Iron Age Warfare, say the Romans. (A recent theory says actually it peaked 12,000 years ago and killed so many males that human survival was at risk.) We do have many strategies to reduce tendencies towards aggression and there has been a lot of natural selection against it, especially since the revolution in weapons that started during the American Civil War that made the instinctive aggressive response strategy far more dangerous. If you read the history of WWI, it tells of the cream of society, marching off to a war that was a slaughter. There are indications, such as reduced testosterone levels, that humans are already a bit less naturally aggressive than they were. There will though be a need for enough aggressive potential to act as a deterrent. That is called balance. Still, clearly in the next ecology, aggression is not going to be a good primary strategy based on reduced potential reward, greater risk and because our next ecology will be a created one and so will be subject to damage. Out ecology is our life support system. Any breakdown of it due to war will be a disaster for all, especially non-combatants. After Hurricane Maria, over 4000 people died just from disruption of medical services.
Now, lets go on to some more subtle stuff.
Human survival instinct is ridiculously powerful. Our reproductive instinct, not so much, though it seems generally stronger in women than men. Our instinct to have sex is ridiculously strong and our reproductive behaviors are released by the sequence of behaviors and events that naturally follow that, but artificial birth control has changed the connection between sex and reproduction. Now that having children is far more of a choice, many people are choosing not to. There is a spectrum though of people with little reproductive instinct and those with powerful reproductive instinct, just as there are those with strong or weak interest in sex. In the natural course, most people will come to be descended from people with strong reproductive instincts and strong interest in sex. Down the road, this will likely be one of humanities greatest challenges. If everyone has great reproductive instinct and drive, some of the greatest dangers of all may occur - overpopulation and demographic warfare. Our reproductive habits must exist with both instinct and strategy balanced.
Think a little more. Some people with strong sex drive are not going to reproduce because they are having too much fun having sex. The outcome of sex is a choice now. Also, porn and "sex toys" are very seductive and getting more so. They are also convenient and for some, addictive. Humans are more than animals though and like the so many other modern distractions, some humans are simply going to make a decision that survival, in the sense of a family, is more important than all the distractions. This is going to be based on moral instinct, moral systems, and our most basic human survival instinct. Ultimately, human instincts, survival strategy (moral system) and choice will be required for human survival.
Sociobiology describes the difference between men and women. It describes male adaptation that is monogamy, a behavior that appears when it takes more resources (or other requirements) to raise the young than the mother alone can easily provide. Humans require a long, demanding developmental period... the longest in nature. Now this may seem counter-intuitive, but men have adapted to monogamy. In ways women are less adapted to it. THey didn't need to. That is a general statement, because human behavior is very fluid, even between the sexes, but as a generality it is true. Women accept monogamy - help from the male (there is a scale of variation), but they will also have children without help which is instinctive, but in humans actually not a good strategy. While men need some general reduction in aggressiveness, women need more adaptation to monogamy. They need more love. Many women, not all, focus 100% of their attention on their children. While it is very important for mothers to greatly focus on their children, they are endangering their "marriage" by completely neglecting their husbands. (Many men know about this, many women too, but it is not universal, just too common.) This is a bad thing for a number of reasons. Going forward, marriages are going to be far more based on choice than need. Women are going to need to give love as a reason for marriage. Before complaining too much, remember that most men will do anything for love and no, I'm not talking about sex. Sex is secondary as a mature person knows.
OK, let's go really weird. We need to be more cooperative to survive in the more complicated society we are developing. We need to be a bit like social insects. Their cooperative behavior allows them to do amazing things working together, but it is hard wired in through their genes. Our cooperative behaviors need to be strategic, learned. That is one of the main points of the book I am currently writing now "Strategy For A New Human Ecology". We will though also need to genetically adapt to that, but it's going to take longer. So what is that strategy we need to be cooperative enough to support the post-tribal social form (civilization)? How can we make civilization work? What strategy and genetic nature do we need? We need to love one another.
It can get even weirder though. So what is the most important adaptation of all that humans need to survive? Well, it's our survival instinct. Have you ever heard of human survival instincts? You've heard of animal survival instincts, "the will chew their leg off to escape a trap". Yet even though we know a human will "cut their arm off to escape a rock", you've probably never heard a term for "human survival instinct". There is no word that comes to mind for it. That's amazing if you think of it, but it is the legacy of our Catholic history. In that belief system, humans have no instincts or that would show that we are animals rather than divine. That is a pretty basic contradiction to their belief about how God made humans. Well, we do certainly have survival instincts and they are powerful. Humans can be impossible to kill while other animals may die if they are in unfamiliar environments. I suspect that that basic survival instinct has been a primary focus of evolution since we left the tribal ecology. I suspect it will retain that great importance for a number of reasons. It also is related to moral instincts (which I'm writing about just now). It may be their root. So, what is the name of "human survival instinct"? There is a name. You know it, but you are conditioned not to think that way. If you knew that word, it would empower your ability to understand people, because it is so often what you are seeing in a person, but without the name, it is hard to recognize. Words are that way.
In that we are under enormous survival pressures due to the huge changes in our ecology that have already occurred, humans are evolving rapidly, perhaps more rapidly than any other species, but it is not physically visible nearly as much as it is strategic. The balances of our instincts and drives are distinctly changing and adapting. Many features of our complex society and strategies require more intelligence. Some of the pressures that our tribal and later ancestors had to deal with are minor problems now. We don't have to outrun our food or lions and tigers and bears. We are though under other pressures that they would not possibly have survived, especially ones that come from population density. Our society and world is far more complicated than theirs was though and as some dangers recede, I definitely see others coming that we didn't face. Oh, and then, of course, there is disease. That is going to be a big challenge to adapt to.
There is a different and longer discussion of human genetics in a short book called Genetics For A New Human Ecology. May I recommend that book if you want to know more about human genetics in the future. It describes why humans will have to husband their genes to replace natural selection, how we can do it and what some benefits might be.
The dangers are greater and closer than they appear, but the potentials are greater than human aspirations.