Like many other denizens of the late 21st century, Sarah Higgins spent the first 75 years of her life coming to grips with the idea that she might live forever -- or what seemed like it. Despite some close calls, she was as healthy as the average 50-year-old woman in the late 20th century had been. A freak infection had destroyed her first heart, but fortunately she had a spare. It was cloned from a sample of her own tissue that had been stored away while she was still a teenager.
Naturally, every year her cancer check turned up a few...