Here's the TOC, gifted by ISFDB
Introduction (The 1980 Annual World's Best SF) • (1980) • essay by Donald A. Wollheim
The Way of Cross and Dragon • (1979) • novelette by George R. R. Martin
The Thirteenth Utopia • [Inquestor] • (1979) • shortstory by S. P. Somtow [as by Somtow Sucharitkul ]
Options • [Eight Worlds] • (1979) • novelette by John Varley
Unaccompanied Sonata • (1979) • shortstory by Orson Scott Card
The Story Writer • (1979) • novella by Richard Wilson
Daisy, in the Sun • (1979) • shortstory by Connie Willis
The Locusts • (1979) • novelette by Larry Niven and Steven Barnes
The Thaw • (1979) • novelette by Tanith Lee
Out There Where the Big Ships Go • (1979) • novelette by Richard Cowper
Can These Bones Live? • (1979) • shortstory by Ted Reynolds
The Extraordinary Voyages of Amélie Bertrand • (1979) • shortstory by Joanna Russ
I told the story of "The Locusts" by Larry Niven and Steve Barnes:
In the first colonization attempt, there are 30 people, couples, who land on Ridgeback. They bring everything they need to make a town, fields, bacterium, and animals. The women are supposed to wait to get pregnant for two years, so Doc can be sure it will be okay. Later, Nat managed to make sure Doc didn't see her not-swallow, and her daughter, Eve, arrives early in a year and some months.
Doc is a little worried about Eve -- her hands, her fingers. And as more babies are born, he becomes even more worried. The mayor, Jase, tries to get Doc to say what's wrong. Eventually, out on a pond fishing (no ponds befor they came), Doc tells Jase that there's something wrong with all the children. He doesn't know if a virus changed by radiation or someone brought something with them or what, but there's a change in their genes. Jase sasy he thinks it's aliens who are changing the genes so they can take over the prepared planet and use humans as slaves.
Every year, Ron, one of the media couple, goes up to the Orion and sends a Year Day message to Earth, although they won't get it for 11 years. Then the colonists have their biggest parties.
Doc keeps looking in the lander's electronic library and finally finds that the children look closest to Pithicanthropus erectus. He shows that to Jase who agrees that they have to tell the entire colony. Jase gathers the group and the colonists are devastated by the news.
As the children grow, they have a lot of hair but a minor vocabulary. Many of the families put their kids (some have more than one) in a complex made just for them. The kids have fun there, but when people take them out for walks, there's a lot of trouble getting the kids out of the trees.
The colonists think the colony is doomed and start walking out, drinking themselves to death, cutting their wrists. They think the only thing that can help is another spaceship from Earth, even though ir will take a long time. One year, Ron goes up for the Year Day message, but the Orion blows up. They no longer have any help.
The colonists decide that all the kids have to be neutered, but Doc refuses to do it. He thinks the kids will develop again into what looks like humans. Others who can do it, however, will. Doc decides he has to let them try to live and gets them all out of the complex (stunning his wife, who was on duty) and deliver them to two different places. He flew the sled into water and swam to shore, finding and living with one set of the kids. The other set is found by the colonists and are being used as semi-slaves anyway, helping in the fields.
Long time passes and Jase walks into his house and finds Doc with Eve and her baby as well as Doc's kids Jerry and Lori. Jase tells him about the colonists and how many are dead and why. That last time that Ron is up in the Orion, he gets a message from Earth that says the colonists have to work out because every child born on Earth now is Pithicanthropus erectus. As Doc and the others leave, Jase asks if he thinks the kids are human. Doc carefully says that he's sure they're humans. On their way back to the forest, he thinks that he knows they're humans because he had tested them the only way he could.
(Two people got that last bit.)