Falling Free by Lois McMaster Bujold is about Leo Graf, an engineer sent to teach at a distant space station. What he finds there ends up turning him into an activist.
His students are a genetically modified human subspecies called "quads" who have four arms instead of two arms and two legs. They are also genetically adapted to live better in the low gravity of off world living. While the have the same intelligence, personalities and hopes and desires as humanity, they are treated by the research company as property and nothing more.
Lois McMaster Bujold excels at world building. The space station, ships and planets in Falling Free are as believable and fascinating as the ones I "visited" in Borders of Infinity.
The problem the book suffers from is its simplicity. The people in charge line up on either side of the line Bujold has drawn, either being for the liberation of the quads or against their very existence. There is no one with any confliction feelings or thoughts to balance out this retelling of Uncle Tom's Cabin as realized in space.