A little time travel story: Early in the 4th Millinnium AD, the earth is devastated by people in space, and in reprisal, earthling humanity destroys all the Solar System. However, there is a happy ending.
The major protagonist goes "back in time" (actually going back in time is logically impossible of course) to guide and control the progress of science. We have chapters of history (the universe, human evolution, religion). People become so advanced that he is arrested and frozen, but he escapes in time for the final resolution of the great war.
He is made (babies are not conceived and born in times to come, but designed and made and hatched from replication mechanisms) according to humanity's original design. The most people are hermaphroditic or sexless, but that's the way it is. He has no idea what he's in for when he enters a universe of people like him. He finds that he really likes sex, and the past doesn't regulate reproduction! He's like a god in the ancient past. Who's going to stop him?