Aliprandi was always intrigued that he did not resemble the four sisters he grew up with. "There was something different," he told The Associated Press by phone. "I had blonde hair and blue eyes and my sisters had dark hair and eyes. I had the typical features of a descendent of German immigrants, while my sisters and parents were of Italian stock. Something did not add up." Aliprandi paid for a DNA test which confirmed his suspicions. Then the hunt was on.
You can read more in an article at http://cbs4denver.com/watercooler/switched.at.birth.2.1837167.html
My thanks to Leslie McVay for telling me about this story.