Apr 25, 2014 07:10 AM EDT By Staff Reporter, UniversityHerald Reporter

The University of Utah (U.) has apologized to a family from Texas for a possible sperm mix up for artificial insemination.

The medical procedures at two now-closed U. clinics were challenged last year after Pamela Branum discovered that her daughter conceived through artificial insemination was in reality the biological offspring of a former andrology laboratory assistant instead of her husband, John.

The DNA of Annie Branum, born in 1992, matches with Thomas Lippert, who was employed from 1988 to 1993 at both the centers - local Reproductive Medical Technologies and the U.'s Millcreek Community Laboratory on 3900 South in Salt Lake City. The family became aware of the sperm tampering following a DNA testing on their daughter in 2013.

The San Antonio couple believes that Lippert deliberately replaced his sperm for John's, The Salt Lake Tribune reports.

University of Utah's Special Review Committee report, released Thursday, did not reveal whether Lippert's actions were intentional or unintentional.

"Such a sample switch is unacceptable, whether caused by the unethical or irresponsible conduct of Mr. Thomas Lippert or any other employee of the University," the report states, Desert News reports.

Lippert passed away from alcohol abuse complications in 1999. Lippert reportedly donated sperm at the labs before and during his employment and managed his donations all by himself.

The University also failed to perform a background check at the time of his employment in 1988. Lippert had pleaded guilty to conspiracy charges, was ordered to receive 90 days of psychiatric treatment and serve two years in a federal prison. He was accused of kidnapping women with the help of another man in Minnesota in the mid-1970s,  nbc reports.

"The University apologizes for the heartache this has caused the Branum family," said Dr. Jeff Botkin, one of the three authors of the report, fox 13 reports.

The report advices the University to continue offering free paternity tests to former patients. An estimated 1,500 couples sought treatment at the U. clinic during Lippert's tenure at the clinic. The report states that the Branum family is not the only victim of a possible intended sample switch, other couples might have also been affected. The University has also not contacted the couples who used the services of both the fertility clinics.

The Branums are not satisfied with the findings of the report. "We are disappointed by what we perceive as a cursory, biased and incomplete investigation on the part of the University of Utah committee," the Branums wrote in a statement. "We know that key witnesses who have knowledge relative to the andrology lab at the U. were not interviewed; consequently, we believe the findings are highly questionable."

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