My name is Joshua Berg. I am white, my wife is black and we have two biracial daughters. My extended family includes members from almost every continent on Earth and represents multiple ethnic identities. In short, we are representative of what is gradually becoming the typical American family. Welcome to my column about raising mixed race children.     The numbers of interracial marriages and unions resulting in mixed heritage traditions are numerous and increasing exponentially. If Norman Rockwell were alive today, he’d need a more complex palette indeed. But, the issues of these families are often overlooked, as this country and the world cling to outmoded ideas of race wherein concerns,...