I so did not see that coming. I'm not sure that the Audience would either, with so much focus on the fertile vs. infertile, then in the end it turns out ALL the women will be needed to bring children to term. And EVERYONE (young or old, man or woman) will be needed to help raise the next generation, nourish them and keep them safe. So awesome!
Talk about learning a lesson in Acceptance!
Note: I think this works well with the OS Solution as written, although it might take a bit of the wind out of the sails of this:
ADDED, by accepting other survivors they find a young pregnant girl and her fertile boyfriend, both of whom would have died outside the colony.
Maybe we would change it finding an older couple and they find out after accepting them into the Colony that the woman is pregnant even though she's both infertile and in her 50s ... because the old guy was the fertility doctor. Or we keep the young people and just include the fertility doctor too, maybe as the girl's father or grandfather, who only gives up his secret after being Accepted by them?