I’m in the middle of Iain M. Banks’ Player of Games. I might post more about the book in general after I’ve finished it but there’s something in it that started me thinking and I wanted to go ahead and throw it out there for (hopefully) discussion.
There is a race of humanoids in this book that has three sexes. In every story I’ve read in which there is a three-sexed race one of the sexes is merely an incubator and makes no genetic contribution of their own. My question for science fiction fans: Have you noticed this and have you ever read (or seen) a science fiction story about a three-sexed race in which each of the three makes a genetic contribution? Also, either way, how scientifically plausible is this arrangement?