Russell Martin is the first person we know to be able to have kids without medical interventions. After his two boys were all grown up, Russell was diagnosed with mosaic Klinefelter syndrome in his mid 40's.  
After extensive research on mosaic XXY, even after his doctors told him there was no way he could have XXY, a karyotype test years later revealed he did.   What is Mosaic Klinefelter syndrome?  Klinefelter mosaics (47, XXY/46, XY) are less severely affected, and the chance of finding sperm in the ejaculate in these males is significantly higher than in nonmosaic (47, XXY) cases.  https://livingwithxxy.org/