Twins — Laurence E. Dahners

This is the seventeenth book in a series of near-future Hard-SciFi Thrillers. Their heroine Ell Donsaii has a nerve mutation that's rendered her a genius as well as providing astonishing athletic abilities. Her genius has let her revolutionize our world with a number of inventions, including instantaneous communications and trans-dimensional portals that deliver fuel, water, and food all around the worldTwins is about events four years after the birth of Ell's twins, Caii and Raii. Only six months after their birth, an abortive kidnapping attempt successfully steals the girls but then loses them at a dirt airstrip in Mexico. Drug runners pick the twins up by mistake and take them to their cartel's boss. This infuriates the chief because he was expecting a delivery of cash. To the boss's astonishment, his infertile wife insists on adopting them!The twins are four and a half (though their adoptive mom thinks they're a year older than that) when a cartel up-and-comer kills their adoptive dad.Without him, they and their adoptive mom must now find their own way in the world.This is the story of how some of the talents they inherited from their mother ease those difficulties.Unavoidably, this book also deals with some of the startling changes the world is going through as it adapts to the transporters Ell and Roger invented in Book 16