Unfortunately, human intelligence is steadily declining. It continues in cycles, upward and downward. See Edward Dutton, At Our Wits End for the case for that.

To the main point, humans have now started to manipulate their genes. Thus, they will inevitably begin to select them. Since genes are massively complicated and contain an overwhelming amount of information, humans will begin to use computers help them make these selections. Over many generations of a sort of genetic 'arms race' will ensue. Those who use computers will outpace those who don't.
Then it's a matter of who has the best computers / algorithms, which will, as a result, continuously improve. Eventually, humans will depend upon the computers to select their genes. The long path of this dangerous trend, is the computers become very advanced and there will be a kind tango between 'humans' and computers. The arms race will lead to the situation where computers that control humans the best will be the most powerful. On and on until neither of them look the same as they did before.

That's the danger humans have over the next many millennia. Not sure it can be avoided. The temptation to edit genes will be not easy to avoid en masse.