Ok, this is going to be a toughie. I remember, vaguely, a book in which an american (I think, at least a westerner) agrees to join a colonization voyage that will take generations, on a world ship built and launched by China. The idea that China would be The world power and leading space agency of the world was one of the big sci-fi predictions made in the book. That's some impressive foresight, since I read the book maybe 17 years ago.
The gist of the story was that humanity was breeding like cockroaches, and they needed to get people off the planet. Morals regarding sexuality have become extremely loose, and people seem to offer sex very gratuitously throughout the story. So basically they get rid of a big chunk of people by sending them off in this world ship. I THINK the book was partly comical or at least exaggerated in its treatment of the stupidity and sexual drive of people and how that would eventually spell disaster for our world.
That's IT. That's all I remember about the story. I don't remember what happens next. I'm not even sure if they reach a destination. I have a vague recollection of the book describing how the people on board the ship just keep breeding and pretty soon they're over populated. The reason I ask is that I was really impressed with the idea that China would become a superpower, since I saw that as improbable at the time. Considering current events, I've become curious as to who wrote the book, and what the story was.