I've been struggling to remember the name of a story. For all my searching, I've drawn a blank. I was hoping someone here might remember it. I'm not sure if it was even published on this site. Or if it was and then later taken down.

Synopsis:

It was a sci-fi setting, on a generational ship. For some reason the Earth was doomed and (I think) an alien race came to Earth and taught humans how to get off the planet. The story starts after the parents of are put into hybernation. During a health check, the boy character, I think his name was Steve, is assigned female by the ship's artificial intelligence. A girl, I think her name was Karen, is assigned male. I believe the story is divided into three books. All the books are about these characters coming to grips with their situation and trying to fix the computer's "mistake."

In the last book they make planetfall and begin to set up a new colony. That's when the computer begins to wake up the kid's parents and grandparents. Along with "security force" made up entirely of (androids? clones?). All named... Ian? Something like that. I'm sorry for my hazy memory. In the third book, I remember Steve was pregnant but beyond that I have no idea.

If anyone has any ideas, please leave a comment. This has been driving me up the wall. Thank you!

Edit: G11 is the name of the story! Thank you all, you're the best! This has been killing me.