Accidental Anomalies

Ever since the meteorite holocaust, mutations have been showing up in the population. Drs. David and Michael Simmons are highly regarded and successful researchers, wealthy philanthropists, and directors of the Center for Genetic Research. They have terrible luck with women, however. When Aspen and Diem, sisters, marry the brothers, like all the other wives, they disappear. What is hidden in the lowest basement of the Center?