Family Sues Gynecologist After He Allegedly Impregnated Woman With His Own Sperm

A Wisconsin family filed an Aug. 6 lawsuit against a former Milwaukee gynecologist for allegedly impregnating a woman using his own sperm without her consent.

Mary Ellen Lukezich and her son Joseph Laedtke Heider sued Dr. Frederick Dettmann, who was Lukezich’s fertility doctor in 1982, according to local outlet WISN. After Lukezich sought treatment, which was unsuccessful, Dettmann suggested she try artificial insemination, according to the lawsuit cited by WISN.

Dettmann allegedly told Lukezich that the sperm donor would remain anonymous and would be a “healthy, young medical school student,” the same lawsuit states. Lukezich and her son learned Dettmann is his biological father after Heider submitted a DNA sample to Ancestry.com in 2024. The results of the DNA sample indicated Heider had multiple half-siblings who Dettmann also fathered.

Heider recalled learning that he had multiple half-siblings, according to NBC News.

“I got an email from Ancestry, which is the company that I ordered the DNA test from, that I had a half-sister,” Laedtke said. “And so when I went into my DNA results and the relationships, I had noticed that there were multiple half-siblings that it had suggested that I was related to,” he continued.

Heider said he immediately called his mother and learned he’d been conceived using donor sperm. She screamed when he told her Dettmann was his biological father.

“What he did was incomprehensible, and it was such a betrayal of trust that I just want to make sure that if I have the opportunity to hold him accountable for the pain that he caused my mom and the things that he put her through that maybe she didn’t even know at the time,” he told NBC News.

Lukezich and Heider are represented by attorney Allan Foeckler, who says he’s been contacted by other women regarding their interactions with Dettmann. Foeckler described Dettmann as a “serial predator of women,” according to NBC News. (RELATED: Police Arrest Middle School Teacher After Authorities Use Brand New Grooming Law)

In addition, Dettmann, now 91, was accused of allegedly assaulting a patient during a gynecological exam in 1985. The patient’s husband filed a police report, but authorities did not bring charges against Dettmann because of difficulties establishing a burden of proof, NBC News reported. Dettmann denied the allegation.

Whitefish Bay Police Chief Patrick Whitaker told the outlet that the department does not have an open investigation into Dettmann, and any records linked to the 1985 accusation would have been destroyed due to record retention laws.

Dettmann is now retired and lives in Arizona, according to NBC News. His attorney, Sean Gaynor, said his client is aware of the allegations that have been made against him.

“The events referenced are alleged to have occurred almost 50 years ago. Dr. Dettmann has no independent recollection of the individuals making these allegations and is unaware of any evidence supporting the claims being asserted,” Gaynor told the outlet.

Lukezich and Heider also plan to file a civil lawsuit accusing Dettmann of battery, according to 12 On Your Side.

The Daily Caller contacted Foeckler and Gaynor, neither of whom immediately commented on the allegations against Dettmann.