Northwestern Memorial Hospital made the claim in response to 40 lawsuits filed against the hospital, the Chicago Tribune reported Tuesday.
The suits claim the hospital and the Northwestern Medical Faculty Foundation, which maintains the tanks, were negligent when a tank containing genetic material and a backup alarm failed during a weekend in April 2012. The failure caused damage to semen and testicular tissue kept frozen in the tank.
The suits claim further that Northwestern staff did not adequately respond when they knew the system had failed.
Northwestern responded to the suits in a statement, saying 'we deeply regret that this equipment malfunction occurred." The statement said specimens in the faulty tank were immediately transferred to another working tank.
Physicians of the foundation contacted 250 patients to inform them of the malfunction.
All of the suits were filed as "John Doe" to protect the patients' identities and conceal any medical problems with which they may have been diagnosed.
The lawsuits charge the lost sperm was the "one and only shot" for many of the men to have biological families.
They charge Northwestern was negligent in putting all the specimens in one other working tank when other tanks were also available.
Three of the plaintiffs were minors at the time of the accident, the youngest a 14-year-old with a rare form of cancer, the Chicago Sun-Times reported.
Matthew T. Jenkins, an attorney for the plaintiffs, said more people were likely affected than the 40 represented by his firm.
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