Sepich says that the back of her business card includes her CODIS profile, to make the point that "the profile doesn't say anything about me." She points out that a DNA swab doesn't capture the entire DNA strand, but instead just a profile of 13 markers isolated from some 3 billion. "Those 13 markers were specifically selected by genetic scientists because they have no potential of revealing anything private about you," she says. "The only way anyone knows who the CODIS profile belongs to is after a match is made."
The case before the Supreme Court Monday centered on Alonzo King, a Maryland man who was arrested six years after the rape and robbery of a 53-year-old woman for another crime, a felony second-degree assault. His DNA swab matched a sample from the rape. The police were able to make the match because Maryland's law already allows for warrantless DNA tests.
At oral arguments in February, Supreme Court Justice Sonia Sotomayor sarcastically noted that if DNA swabs work so well, "why don't we do this for anybody who comes in for a driver's license?"
That sort of big brother scenario is what privacy advocates most fear: that the government would turn to DNA profiles as a tool to track citizens.
"The same way that the social security number has become a ubiquitous identifier, you could imagine using DNA. It's a lot harder to fabricate. Instead of having someone fill out forms at the doctor's office, why not swab someone's cheek," says Murphy, the NYU law professor. "I think those are real concerns."
In court, Baltimore deputy attorney general Katherine Winfree argued that the benefits of DNA swabs outweighed the risks, noting that since 2009, the year Maryland starting collecting DNA samples from people arrested for serious crimes, police had made 225 matches, 75 prosecutions and 42 convictions.
Sepich agrees with the sentiment, but her reasons are a lot less numbers-based and a lot more personal.
"Probably thousands of families in the U.S. will not go through what our family went through, now, because DNA will be used to not only solve crimes but prevent crimes," she says.