My (STEP)FATHER WAS BORN ON jANUARY 26TH. I am the eldest of my mother's three children, but the only one not related by blood to him. MY ELDEST SON, HIS FIRST GRANDCHILD, WAS BORN ON JANUARY 26TH. MY HALF BROTHER'S ONLY SON WAS BORN ON JANUARY 26TH. Significantly, on my father's 65th birthday, my son was 21 and my brother's son was 18.