SPRINGFIELD, Ill. (CBS) — The State of Illinois says it has received more than 4,000 applications from adoptees who want copies of their original birth certificates.

As WBBM Newsradio’s David Roe reports, before a new law went into effect, the original birth certificates of adoptees were sealed and new ones were issued when the adoptions were final.

LISTEN: WBBM Newsradio’s David Roe reports

But the 2010 Illinois Adoption Act allows adoptees ages 21 or older and born after Jan. 1, 1946, to ask for non-certified copies of their original birth certificates. Once they have them, the adoptees can possibly learn the names of their biological parents.

However, the law also allows birth parents to keep their information confidential.

The law is taking effect in phases, the most recent of which was last month. In that month, 4,184 applications for birth certificates came in, of which 556 were not fully completed or did not include adopted names, the Bloomington Pantagraph reported.

The state has provided 150 original birth certificates so far, the Pantagraph reported. Among those 150 was state Rep. Sara Feigenoltz (D-Chicago), the sponsor of the legislation and an adoptee herself, who received her original birth certificate on Dec. 9 but has yet to look at it, the newspaper reported.

A total of 431 parents have requested anonymity, the Pantagraph reported.

(TM and © Copyright 2011 CBS Radio Inc. and its relevant subsidiaries. CBS Radio and EYE Logo TM and Copyright 2011 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten or redistributed. The Associated Press contributed to this report.)