Twenty-five years ago, two Argentinean grandmothers flew thousands of kilometers to knock on the door of New York-based Argentinean geneticist Victor Penchaszadeh to ask him to reunite their broken families. A few years earlier, armed henchmen had burst into their children's homes and the homes of thousands of other Argentineans considered to be political dissidents, spiriting them away to secret detention centers. Many were never seen or heard from again.
One 1978 night, gunmen took Argentineans Claudio and Monica Logares and their 23-month-old child, Paula. Like hundreds of children either abducted with their parents or born to captive mothers, Paula grew up in the...