Takes two Individual records as parameters and returns TRUE if they share some part of their X chromosome(s) - or at least if they would share some part of their X chromosome(s) if chromosomes were infinitely divisible. Males inherit their X chromosome exclusively from their mother. Females inherit X chromosome from both parents. So this function would return FALSE for a father and son, but would return TRUE for a father and daughter, or for a mother and child of either sex. The function takes no account of the actual percentage of shared X chromosome, which typically halves with every generation that you go back.
A reference to an Individual record..