A routine DNA test led to a stunning discovery for one family: a woman’s son had nine half-siblings, and all appeared to be genetically tied to her former gynecologist.
Mary Ellen Lukezich and her late husband, Thomas Laedtke, turned to Dr. Frederick Dettmann for fertility treatment in the early 1980s after struggling to conceive. The couple eventually chose artificial insemination in hopes of having a child.
According to NBC News, Lukezich said Dettmann told her the sperm would come from a medical student donor who lived out of state and resembled both her and her husband.
“I was young,” said Lukezich, who is now suing the doctor. “I so wanted to be a mom that I was going to do anything, and I did whatever he asked me to do.”
The treatment resulted in a pregnancy, and Lukezich gave birth to her only son, Joe Laedtke, now 43. In December 2024, he took an Ancestry DNA test simply out of curiosity — and the results were far more unsettling than he expected.
“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 was multiple half-siblings that it had suggested that I was related to.”
Laedtke said he only learned he had been conceived with donor sperm after calling his mother about the results. Lukezich was shocked, and Laedtke said the apparent revelation that Dettmann was the donor left him feeling “disgust and disappointment” over what he viewed as a serious breach of trust by his mother’s physician.
“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 the outlet.
“I feel like I’ve been raped,” Lukezich said. “And it’s not right. And I want other women to feel OK about coming forward with this.”
Last week the family filed suit against Dettmann, and their attorney, Al Foeckler, said numerous women have reached out to him since they disclosed their unusual situation, saying they had problematic interactions of their own with Dettmann dating back to the 1970s.
He’s encouraging other women who may have been impacted to come forward.
“There is no question in my mind that this man was a serial predator of women,” Foeckler told NBC News.
The suit does not seek a specific amount of damages and is instead requesting a court determine the amount at the trial.
Dettmann, 91, retired in the 1990s and now lives in Arizona.
His attorney, Sean Gaynor, said in a statement that the former clinician knows of the allegations but is unable to address them because of privacy laws.
“The events referenced are alleged to have occurred almost 50 years ago,” Gaynor said. “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.
A report filed by the husband of one of Dettmann’s patients in 1985 alleging he had assaulted his wife during a gynecological exam in Wisconsin, however the doctor denied the allegations and the charges were later dismissed because it was “too difficult” to prove he had acted inappropriately.
Records show the complaint was reported to the medical licensing board but closed in 1986 after a vote and consideration of the facts.
Whitefish Bay Police Chief Patrick Whitaker told the outlet that any case records would have been destroyed due to the state’s retention laws, and that there is no open investigation into Dettmann with the department.
Gaynor pointed out that Dettmann was “never sued, disciplined, investigated, had his licensure challenged nor were there any ethical complaints made against him.”
