## Facts

- Alfred Ivey, Jr. lived in Hardin County, Kentucky with his half-sister, Novina Peel, and Peel’s daughter, “Karen” (a pseudonym), for many years.
- When Karen was 13, she became pregnant and later gave birth. At the time, Karen and Peel told others that Karen had been raped at a school dance, and Peel raised the child.
- Years later, after Karen had moved out of state, she reported that Ivey had repeatedly forced her to have sexual intercourse when she was about nine to eleven years old and again when she was thirteen, resulting in the pregnancy. Karen identified Ivey as the child’s father.
- A civil child-support action led to a court-ordered DNA paternity test. In connection with the criminal investigation, police later obtained a second DNA sample from Ivey pursuant to a search warrant.
- The Commonwealth presented DNA paternity evidence described as a three-step process: (1) comparison at 15 DNA loci to determine whether Ivey could be excluded, (2) calculation of a paternity index, and (3) conversion of that index into a probability of paternity by combining it with a “prior probability.”
- The examiner testified that Ivey was not excluded because the profiles matched at all 15 loci; the paternity index indicated Ivey was approximately 11,900,000 times more likely to be the father than a randomly selected male of the same race.
- Using a standard 50% prior probability commonly used in criminal cases, the examiner reported a 99.9999% probability of paternity and also testified that even much lower priors still yielded a probability exceeding 99.99%.
- Ivey moved to exclude the probability-of-paternity testimony and sought an evidentiary hearing to challenge the statistical approach. The trial court held a hearing and denied the motion.
- A jury convicted Ivey of two counts of first-degree rape, and he received a life sentence. He appealed to the Kentucky Supreme Court as a matter of right.

## Issues

1. Whether the trial court abused its discretion under KRE 702 by admitting testimony about a probability of paternity calculated by combining a paternity index with an assumed 50% prior probability.
2. Whether the DNA witness improperly invaded the jury’s role by explaining how the probability-of-paternity figure should be understood in deciding whether Ivey was the child’s biological father.

## Decision

- The Kentucky Supreme Court affirmed Ivey’s convictions and life sentence.
- The Court held that the trial court did not abuse its discretion by admitting probability-of-paternity testimony derived from a paternity index and an assumed prior probability, where the method was generally accepted in paternity testing and Ivey did not show it was unreliable.
- The Court rejected Ivey’s claim that he was denied a hearing, concluding the trial court in fact conducted the type of evidentiary hearing he requested and reasonably found his materials did not justify exclusion.
- The Court held the witness did not improperly take over the jury’s function; the testimony explained scientific calculations and their meaning rather than directing a verdict or stating that Ivey was criminally guilty.

## Legal Principles

- Under KRE 702, a trial court may admit scientific testimony if it is based on reliable methods and will help the fact-finder understand the evidence or decide a fact in issue; appellate review is for abuse of discretion.
- A party challenging an otherwise accepted scientific method may be required to show the method is not reliable (or is no longer reliable); presenting limited materials that do not persuade the trial court generally goes to weight, not admissibility.
- DNA paternity testing may be presented through (1) inclusion/exclusion at tested loci, (2) a paternity index comparing the likelihood of paternity to a random male, and (3) a probability-of-paternity figure that combines the index with a stated prior probability.
- Use of a conventional 50% prior probability in a probability-of-paternity calculation is not automatically improper when the assumption is identified for the jury and the testimony explains what the figure means.
- An expert witness may explain how to interpret technical statistical results without invading the jury’s role, so long as the witness does not instruct the jury to convict or offer a legal conclusion on guilt.

## Conclusion

In *Ivey v. Commonwealth*, the Kentucky Supreme Court affirmed rape convictions where the Commonwealth introduced DNA paternity statistics showing an extremely high likelihood that the defendant was the child’s father; the Court held the probability-of-paternity calculation (including a 50% prior probability) was properly admitted under KRE 702 and the testimony helped the jury understand the DNA evidence without telling the jury what verdict to reach.


Ivey v. Commonwealth, 486 S.W. 3d 846 (2016)