 What is NOT a reason that a child probably shouldn't read this?
Extensive research did not uncover any evidence that the U.S. copyright on this publication was renewed.] "There are at least a hundred kinds of humans, each supposedly originating in strict seclusion on as many widely scattered planets. Obviously there was no contact throughout the ages before space travel— and yet each planetary race can interbreed with a minimum of ten others ! "Outside of your own world, there's nothing like your species, except superficially, and that's true of all other creatures, intelligent or not, with the sole exception of mankind. Actually, the four of us here, though it's accidental, very nearly represent the biological spectrum of human development. It's reasonable to assume that, if men were set down on a hundred such worlds, they'd seem to fit in with native life-forms on a few of them. That's what happened on Earth; when Man arrived, there was actually a manlike creature there. "But there are other worlds in which humans who were there before the Stone Age aren't related to anything else there. "Something had to distribute one species so widely and it's not the result of parallel evolution—not when a hundred human races are involved, and only the human race." "We've got new data and are able to interpret it better. The theory is that humans who can mate with each other were once physically close. When we project back into time those star systems on which humans existed prior to space travel, we get a certain pattern. And while stars in a given region tend to remain together, there's also a random motion. "And whereas there are humans who are relatively near and not fertile, they can always mate with those they were adjacent to two hundred thousand years ago !" "However, we have other ways of dating it. And, of course, if it were a fast-moving star, it might be completely out of the field of our exploration. Anyway, non-humans weren't trained in the fine distinctions that men made among themselves. We have men who could do the job in a makeshift fashion, but the region we're heading for, while mapped, is largely unknown. "I had other plans, but I can't evade professional obligations, and an emergency such as this should cancel out any previous agreements. "You can read it if you want," offered Taphetta. However, you needn't be afraid that I'm defrauding you.
 There was gun violence (with space rays)
 There was casual sexism  There were implications of sex  There was gun violence (with space rays)  There was abuse between partners