No. We don't know *how*, but we know it can be done and is done every minute of every day by biological processes.
The knowing how is the problem. While there is little down that a human level AI could be built if we knew what to build, it is not clear that we are smart enough to come up with a design in any kind of directed fashion.
“If our brains were simple enough for us to understand them, we'd be so simple that we couldn't.”
Ian Stewart, The Collapse of Chaos: Discovering Simplicity in a Complex World
This is conjecture, of course but there is scant evidence against it. Some AI researchers have taken this philosophy or something similar to heart and propose that the only way to make real progress in AI is to reproduce the processes that lead to the human brain: random changes and selection pressure. The trouble is, even if it works and a human AI comes out of it (and it is no clear that we are even smart enough to provide the right selection process), it seems we would have little control and less understanding of the result. Benign but useless seems the most likely outcome.