Oct. 29, 2013— -- Paul Fronczak is a man on a mission.
From the day he got the results of a DNA test and discovered that he was not the biological child of his parents – that he is not the newborn who was kidnapped from a Chicago hospital – Fronczak has dedicated his life to finding out where the kidnapped baby is, and his true identity.
The hardest part for Paul Fronczak is how his obsession has caused pain to his parents, whom he loves so deeply.
Chester and Dora Fronczak brought Paul home as a toddler and believed he was their missing child. They raised him in a warm, loving family. They have asked Paul to drop his search -- because it raises too many painful memories. Paul's wife Michelle says she doesn't "think they want to stir up those old memories."
But for Paul, his search has nothing to do with whether he was happy as a child – he feels that truly knowing his past will allow him to understand his future.
In every interview with me, Paul has expressed that his unusual past, being discovered as a toddler on the streets of Newark, N.J., and being placed in foster care until Chester and Dora Fronczak brought him back to Chicago, caused serious consequences in his adult trajectory.
"I think that being bounced around from family to family at such a young age has really left me not having a direction of who I am. I've had probably 100 jobs in my life. I think it's because I really didn't have that firm foundation."
Paul is currently a college administrator at a school near Las Vegas.
The greatest foundation and joy in Paul's life are his wife Michelle and 4-year-old daughter Emma.
Michelle, a school teacher, was surprised when Paul first told her about his unusual past on one of their first dates: "I thought he was just kidding around. The first story, the first time through I thought it was a joke." But after seeing the newspaper clippings about the 1964 kidnapping earlier, she understood that for Paul, this was no joke.
Michelle and Emma are Paul's anchor and lifeline.
Despite Paul's questions about his own identity, Michelle knows exactly who she married: "As far as I'm concerned I'm Mrs. Fronczak, because he is Paul Fronczak. He's not the biological Paul Fronczak, but he's--we're the Fronczak family. So it makes no difference to me."
I asked him if he was obsessed with his quest, and he agreed: "Once you get that information, you just can't go, 'Oh, now I know. I'm just gonna move on.' I'm not that-- I'm not wired like that."
ABC News Anchor Barbara Walters and Chief Investigative Reporter Brian Ross are investigating the case. Do you have any tips on this case? Click here to send them to ABC News.
You can also contact the FBI by emailing Chicago@ic.fbi.gov or calling 1-800-CALL-FBI. You can see another age-progression picture of the real Paul Fronczak at the National Center for Missing and Exploited Children.