A decent, if short, story, Yesterday's kin begins when Marianne, an evolutionary geneticist, is taken by the FBI to the UN. She doesn't understand why. Even though she's just made a discovery about human evolution - she helped identify a new sub-group of humans who share a common ancestor who lived 150,000 years ago - she knows she's nothing special. She's just a work a day scientist who made a discovery rather than proving an brilliant theory or inventing an elegant equation. She's more worried about her children, who constantly fight with each other when they happen to see each other, or with her when she gets a chance to see them when she's not working. She's most concerned about Noah, her youngest who doesn't fit in anywhere, and is addicted to a new drug that permits you to feel like someone else for a short time.
It turns out the Aliens that arrived several months ago want to see Marianne, they are very interested in her genetics research and want her to continue it inside their alien Embassy floating in New York harbour.
The aliens are friendly, or so they claim, but no-one has seen them. They eventually do show themselves, and they look a lot like us. They come baring bad news, the earth will soon be moving through a gigantic spore cloud that will kill all humans, they know as some of their colonies have been wiped out from the same cloud. They request humanities best scientists to help them find a cure that can help both the aliens and humanity, but they've only got 10 months to do it. Can the world's top scientists achieve that? Why are the aliens so secretive, why don't they share their own research with the humans? With riots, shootings and terrorists, will humanity even survive long enough to be destroyed by the spore cloud?
Kress explores genetics, family politics, and human psychology all in an easy 200 pages.