OP-ED CONTRIBUTOR Cleveland TODAY is my birthday. April 17 is what's on my driver's license and other documents. But I don't know for sure, and probably never will. All I know is that I was born in Cambodia, sometime during 1970. In Cambodia, we didn't celebrate birthdays, so while my mother and father knew the date, I had no reason to remember it. Instead, my early years were marked by joyous events like the New Year, the Water Festival and various Buddhist holidays. In the early 1970's, Southeast Asia was full of strife; the Soviet Union, China and the United...