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Editor: Colin Miller

No Pregnant Pause: Illinois Court Rejects Defendant’s Attempt To Analogize Home Pregnancy Tests To Polygraph Tests

By Colin Miller

As I noted in my post on Tuesday, in most jurisdictions, polygraph evidence is per se inadmissible. The conventional wisdom is that polygraph results are a lot less reliable than people, including jurors, think them to be. So, does the same logic apply to home pregnancy tests? That was what the defendant claimed in People v. Prather, 2012 WL 5295801 (Ill.App. 2 Dist. 2012). So, how did the court rule?

In Prather, Clarence Prather was charged wuth two counts of aggravated battery (victim pregnant), one count of obstructing justice, and two counts of domestic battery.  Prior to trial, the State filed a motion in limine seeking permission for the alleged victim (B.R.) to testify that she had used a home pregnancy test kit and had shown the positive result to the defendant.

Among other arguments, “Prather compare[d] home pregnancy tests to polygraph (“lie detector”) tests, the results of which may not be used as evidence.” The Appellate Court of Illinois, Second District, disagreed, concluding that

The supreme court has explained that polygraph tests pose a special danger because they suggest to jurors that they need not make their own credibility determinations (because the polygraph will tell them who is lying), but the tests are not sufficiently accurate and reliable to prove guilt or innocence….By contrast, home pregnancy tests do not purport to “testify” about the credibility of defendants or others, and thus do not encourage the jurors to abdicate making their own credibility assessments. Although the defendant argues that home pregnancy tests might have a tendency to over-persuade a jury in excess of their actual reliability, they are no different from other forms of scientific evidence or test results in that regard, and their reliability may be challenged at trial in the same manner. Accordingly, there is no basis for extending the per se bar against polygraph evidence to home pregnancy tests.

-CM