Poor Relations — Jo Walton

An eye-opening and entertaining tale of social and financial precarity in the interplanetary future, brilliantly imagined and entirely pertinent to today.

It's the twenty-fourth century. Humanity has spread throughout the solar system―but for most of us, life is as precarious as it was in Dickensian England. And while individuals can change their sex at will, traditional gender roles are enforced with unyielding severity.

Brothers Achille, Marcantonio, and Nore have been raised rich, but after their father spends the family fortune and puts a laser to his head, they're forced to face facts. The wealthy Luke Bailey is willing to pay top dollar for what's left of their estate, enough to buy Achille a commission in the space Navy. But only if Marcantonio and Nore will both become female―Marcantonio to marry Luke, and Nore to be their spinster housekeeper, for as long as Luke lives.

Over the next two decades, the now-female Marcantonio and Nore struggle to make lives for themselves in the service of their wealthy keeper. Then the alien invasion arrives.