Today the Supreme Court, in a rather staid opinion by Justice Kennedy, joined by Chief Justice Roberts and Justices Breyer and Thomas, upheld the Maryland law that requires individuals arrested and detained for major crimes to submit DNA samples that can be checked against a database of DNA profiles from unsolved crimes. Justice Scalia, wrote a bitter and sarcastic dissent for himself and Justices Ginsburg, Kagan, and Sotomayor.
I think the question is more delicately balanced than either opinion indicates. For more detailed comments, see the Forensic Science, Statistics, and the Law blog.
Maryland v. King, No. 12-207 (U.S. June 3, 2013).
Kaye, David H. 2013. “A Fourth Amendment Theory for Arrestee DNA and Other Biometric Databases.” University of Pennsylvania Journal of Constitutional Law 15(4): 1095-1160.