The Chromosomal Code — Lawrence Watt-Evans

A sudden ice age has driven Earth's population into the tropics, except for a few die-hards eking out a tenuous existence scavenging the snow-covered ruins of civilization. One such straggler is John Starkman, making his home in the frozen wastes of western Pennsylvania. Already an outcast because of a certain physical peculiarity, he saw no reason to join his neighbors in fleeing south. Then one day a spaceship comes to collect him and the other stragglers, and Starkman discovers there have been other changes besides the ice age. Aliens have landed on Earth. They say they've come to help -- but what do they really want? And why are they interested in him? A science fiction novel by Hugo-winner Lawrence Watt-Evans, back in print for the first time in over twenty years.