 Kirkpatrick had an extremely private, Muslim marriage ceremony in which he wed a local Hyderabadi Sayyida noblewoman called Khair-un-Nissa, who was fourteen years old, not an unusual age for the marriage of girl of her social class.She was the granddaughter of Nawab Mahmood Ali Khan, the prime minister of Hyderabad.However, the marriage was not recorded and does not appear to have been legally valid; in his will he described the offspring of the relationship as his "natural" children, a polite euphemism for illegitimate children that a father recognized as his own offspring.