Infertile couple study
A retired fertility doctor used his own sperm at least 50 times on his patients beginning in the 1970s. BSIP/UIG/Getty

A retired Indiana fertility doctor used his own sperm instead of donated sperm on his patients at least 50 times and impregnated at least eight women decades ago, court documents reveal. The 77-year-old pleaded not guilty on Monday (12 September) to charges in Marion Superior Court.

Donald Cline pleaded not guilty to two felony obstruction of justice charges for misleading authorities who were investigating complaints from two of the now-adult children against him, CBS News reported.

A probable cause affidavit revealed that the Indianapolis doctor told six adults who believed they were his children that he had used his own sperm about 50 times since the 1970s.

Cline reportedly told his patients they were actually receiving sperm donated by medical or dental residents or medical students. He also said no single donor's sperm was used more than three times.

According to CBS News, one of the adult children discovered she was related to at least eight other people in a database for private personal genomics company 23andMe after taking a saliva-based DNA test.

The woman then contacted a local news station, which connected the eight and confirmed they were siblings in subsequent DNA tests.

Two other children found their parentage through DNA tests, which revealed they were related to 70 of Cline's relatives, and discovered their mothers had also been patients of his. None of the siblings were identified in court documents, NBC News reported.

The affidavit said Cline told the adult children "he used his own sperm whenever he didn't have a donor sample available". Court records add that Cline said he "felt that he was helping women because they really wanted a baby."

An unidentified donor child said: "It is very sickening to think he ran his practice up until the time he was about 70".

In a letter to the Indiana Attorney General's Office at the beginning of the investigation, Cline denied ever having used his own sperm. "I can emphatically say that at no time did I ever use my own sample for insemination," he said.

According to WTTV, some of Cline's biologically children say they simply want to know how many siblings Cline produced with his DNA.

Cline's attorney noted that the charges against him "arise solely from his written response to inquiries from the Indiana Attorney General's office and nothing more. He is not accused of hiding documents, influencing witnesses or otherwise not cooperating with the AG's investigation."

He will appear in court again on 17 October.