CHICAGO (CBS) — Who do you look like? Where’d you get your sense of humor? If you were adopted, you may not know.

But as CBS 2’s Roseanne Tellez reports, a new Illinois law is giving thousands of adoptees a chance to find answers to those questions.

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Beginning Tuesday, adult adoptees can apply for a copy of their original birth certificate.

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Donna Haag, who grew up in a loving adoptive family, already learned her biological parents have died, but also that she has a sibling. Getting her birth certificate means she’ll now have the key information – her parents’ first and last names — to try to find them.

“If there’s any information about an older sibling, I’d love to find out,” she says.

Adoptees have always found ways to search for a parent. David Wywialowski was able to forward a letter to his birth mom, through the agency that handled his adoption, Catholic charities.

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He treasures her written response, the first contact he had with a blood relative. But she declined to meet him.

“That was just totally amazing,” Wywialowski says. “This was now my first contact with a blood relative.”

But she declined to meet him.

“There’s a whole mixed bag of ways that it can turn out. Do not go into it a reunion with too many expectations.

While Wywialowski did track down his father, it was too late for a meeting. He had died, leaving behind two sons – David’s half-brothers. He found them.

“These connections were really amazing to me and blew me away,” he says.

A lot of adoptees are more interested in learning medical histories than connecting with relatives. And some just want a birth certificate, the paper that the rest of us may take for granted.

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Biological parents who want to remain anonymous may have identifying information deleted from those birth certificates. For more information about the new law, click here.