Generally, the answer is yes.
Under Illinois case law, extracting your DNA is a search within the Fourth Amendment. Therefore, police must have either a warrant or probable cause before forcing you to submit it. Otherwise, you may voluntarily refuse to provide a sample. See People v Ealy.
Because your right to refuse to give a sample is constitutionally protected, the state may not use your refusal to show that you had consciousness of guilt at trial.
Once police have arrested you, they may take a cheek swab. The U.S. Supreme Court has held that such a swab is no more intrusive than taking fingerprints or mugshots and can be done as part of a booking procedure. See Marilyn v King.
If you have been charged with a criminal offense, contact an experienced criminal defense attorney immediately. An attorney can review your case to help present the best possible defense. If police acted illegally, an attorney may be able to petition the court to have any illegally collected evidence dismissed. Even if police acted properly and the evidence against you is overwhelming, an attorney who is respected in the courthouse may be able to negotiate a more favorable plea agreement than you could on your own.
If you have questions about this or another related Illinois criminal or traffic matter, please contact Matt Keenan at 847-568-0160 or email email@example.com.
(Besides Skokie, Matt Keenan also serves the communities of Arlington Heights, Chicago, Deerfield, Des Plaines, Evanston, Glenview, Morton Grove, Mount Prospect, Niles, Northbrook, Park Ridge, Rolling Meadows, Wilmette and Winnetka.)