Wisconsin woman sues fertility doctor for paternity fraud after discovering he fathered her child

A woman in Wisconsin is suing her fertility doctor after discovering he fathered her child instead of the 'healthy young medical school student' donor she was promised, a shocking lawsuit has claimed. Mary Ellen Lukezich, 71, was a patient of Dr Frederick Dettmann over 40 years ago when she was artificially inseminated with a donor's sperm. Now, Lukezich and her son, 43-year-old Joseph Laedtke Heider, are suing Dettmenn, now 91, after they discovered Heider allegedly had nine other half-siblings fathered by the doctor.

'Words cannot fully express what it feels like to learn that your entire identity is built on a lie,' Heider said at a news conference in June. In December 2024, Heider submitted his DNA to Ancestry.com and made the shocking revelation that Dettmann was his biological father. The suit stated clearly that upon tracing these DNA connections, Joseph identified a direct genetic link to Dr Dettmanns' family; that information established that Dr Dettmann is Joseph's biological father.

Lukezich had been a patient of Dettmann's in 1982 and, after medication and surgical treatments proved unsuccessful, he recommended she try artificial insemination. According to the filing, Dettmann told her that the donor would be an anonymous 'healthy young medical school student.' Instead, the lawsuit alleged that Dettmann used his own sperm during the procedure which led to the birth of her son, Joseph, the following year. The anonymous medical student donor that my mother was promised as my biological father never existed. Instead, the DNA led back to one person. Doctor Frederick Dettmann, the very doctor my mom trusted to help her have a child.

The lawsuit was filed on August 6 by their attorney Al Foeckler, with the Wisconsin Health Care Liability Insurance Plan and ABC Insurance Co also listed as defendants. 'These families come to fertility doctors at their most hopeful and their most helpless time,' Foeckler said. Trusting completely in the physician who holds their dreams of parenthood in their hands. Dr Frederick Dettmann preyed on that desperation. He exploited that trust. The since-retired doctor denied any wrongdoing in a statement submitted by his legal team on his behalf. 'The events referenced are alleged to have occurred almost 50 years ago.

Dr. Dettmann claims he has no independent memory of the people making these accusations and knows nothing about any proof supporting them, WISN reported via a statement from his legal team. The filing notes that the doctor told her the donor would be an anonymous healthy young medical school student. This since-retired physician denied any wrongdoing in that same statement submitted on his behalf. Whitefish Bay police records show Dettmann had been accused of assaulting a woman during a genealogical exam back in 1985, as TMJ 4 reported. No charges were issued because proving the assault would be too difficult, according to the outlet. The Daily Mail contacted Wisconsin Health Care Liability Insurance Plan and ABC Insurance Co while trying to reach Lukezich, Heider, and Dettmann for comment. Access to such information remains strictly limited and privileged in these matters. Communities face real risks when allegations surface without clear evidence or accountability. A conservative view suggests that legal systems must balance difficult proofs against the need for justice. Vivid descriptions of past events do not replace hard facts needed in court. The situation demands a logical approach grounded in available records rather than speculation.