The singularity, where humans merge with artificial intelligence will happen by the end of the century. Also, advances in medicine, tissue cultures, robotics, nanotechnology... etc will mean that soon humans will have the ability to live pretty much indefinitely without aging. As this story continues to unravel, the human race is going to be left with something of a dilemma. If we're going to live indefinitely, we can't keep breeding as the planet's resources are finite and there's no reason to believe that colonizing planets outside of our own solar system will ever be feasible due to their great distance.
In the future, we will either have to stop having kids or allow people to reproduce but then withhold technological advances from those who breed so that they die at a normal age.
We live in a very interesting and potentially dangerous period of mankind's existence.