Task: Question Generation
Input (English): Background Paragraph: Klinefelter's syndrome is caused by the presence of one or more extra copies of the X chromosome in a male's cells. Extra genetic material from the X chromosome interferes with male sexual development, preventing the testicles from functioning normally and reducing the levels of testosterone. Triple X syndrome (trisomy X) results from an extra copy of the X chromosome in each of a female's cells. Females with trisomy X have a lower IQ than their siblings. Turner syndrome results when each of a female's cells has one normal X chromosome and the other sex chromosome is missing or altered. The missing genetic material affects development and causes the characteristic features of the condition, including short stature and infertility. 
Story: Two brothers born three years apart were very different. Jim had no genetic abnormalities, while Danny had Klinefelter's syndrome.
Output (English): Which brother didn't have any extra copies of the X chromosome in his cells?