An Indianapolis fertility doctor is facing criminal charges for allegedly lying to state investigators about using his own sperm on patients.

Donald L. Cline, 77, is charged with two felony counts of obstruction of justice for allegedly making false statements to the state attorney general’s office in 2015.

Prosecutors say the now-retired specialist may have used his own semen on patients 50 times during the 1970s and 1980s.

The investigation was sparked by two Indiana women, now in their mid-thirties, who matched as siblings on a DNA testing website. Indeed, a paternity test revealed Cline as the women’s biological father in August, court papers reveal.

On Monday, Cline surrendered during a court appearance in Marion County and was released on his own recognizance. He has pleaded not guilty.

If convicted on both counts, Cline would face a maximum five years in prison, deputy prosecutor Tim DeLaney told The Daily Beast.

“For our purposes, this is an obstruction of justice case. It’s important, no matter what the passage of time is, to respond completely to the best of your ability. Lying gets you in as much trouble as the act itself,” DeLaney added.

Cline’s attorney, Tracy Betz did not return messages left by The Daily Beast but provided a statement to the media noting that “the charges arise solely from his written response to inquiries from the Indiana Attorney General’s office and nothing more.”

The Marion County prosecutor’s office began investigating Cline after four siblings filed complaints against him with the Indiana attorney general in December 2014. The probe was also spurred by a Fox 59 story.

In May 2015, two unidentified women told the TV station they suspected Cline was their father after they matched in a 23andMe online genetic test, which traces ancestry through saliva samples.

“I went from being an only child to having at least eight siblings overnight,” one woman, identified only as Carrie, told Fox 59 last year. (Her claims were echoed in court papers in Cline’s criminal case.)

Carrie thought she was an only child until a DNA test revealed a family secret: Her biological father wasn’t her dad, Fox 59 reported.

She said her parents’ fertility specialist claimed to use fresh sperm from a doctor-in-training and that he assured the couple the donor sperm would not be used for more than three successful pregnancies.

“I don’t think it is fair to have to have my children, if they start dating someone, to have to have a DNA test just to make sure they aren’t cousins,” said another sister, identified as Julie, in the Fox 59 segment.

The women found six other siblings, all born over a span of eight years, through DNA testing. They questioned how one medical resident could be a sperm donor at the clinic during that period of time, Fox 59 reported.

Indeed, the time span between the youngest and oldest sibling is eight years, a probable cause affidavit filed Sept. 9 states.

The affidavit identifies Cline as the biological father of two women, whose parents used him as a fertility doctor in the early 1980s.

In a meeting with the siblings this spring, the bearded and bespectacled specialist allegedly admitted to utilizing his sperm whenever a donor wasn’t available—and that his sperm could have been used up to 50 times, the affidavit says.

One woman had called Cline after learning her parents used a fertility doctor, the affidavit says. The doc allegedly told her he recognized her parents’ names but their records were shredded. There was no way to find her sperm donor, he said.

So she signed up for the Donor Offspring, Parent & Sibling Registry on amfor.net in an attempt to find potential siblings, court papers say. She soon discovered she had at least two sisters, the affidavit states.

The newfound sisters took DNA tests on 23andMe in 2014 and matched to five other potential siblings sired by Cline, court papers allege.

Then the women fashioned a family tree through the genetic testing site and learned they were genetically related to 70 of Cline’s relatives, the closest being Dr. Cline’s first cousin, the affidavit says.

But without a DNA test from Dr. Cline, the siblings weren’t positive if Cline or his kin was the sperm donor, court papers say.

One sibling sent a Facebook message to Dr. Cline’s family. Cline’s son, Doug, allegedly responded. The women met with Doug Cline, along with his sister Donna, at a church in Brazil, Indiana, court documents reveal.

During the March 2016 meeting, the Clines allegedly claimed their dad told them he donated to a sperm bank eight times or less. When the women balked, Doug Cline went back to his father, who then changed his story, the affidavit states. The doctor allegedly confessed that he had other children out there and that he provided his sperm over a seven-year period.

One woman again contacted Doug Cline, who “asked her to keep the story a secret,” court papers allege. She refused, and asked to meet Dr. Cline face to face, prosecutors say.

The women got a meeting with Dr. Cline at the Almost Home restaurant in Greencastle, Indiana, where Cline allegedly claimed his wife was “supportive” of his sperm donations.

When asked how many times he donated his genetic material, Cline replied, “around 50 times,” the affidavit alleges.

Cline “felt that he was helping women because they really wanted a baby,” the document claims.

The fertility doc also “felt pressure to use his own sperm because he didn’t always have access to fresh sperm,” the affidavit says.

Cline allegedly told the women he never used a sperm bank at his clinic, contradicting Doug and Donna’s previous claims.

Rather, Dr. Cline explained that he “kept track of which patients received his sperm because he put an asterisk on their charts,” the affidavit says.

If parents wanted another baby, Cline would again use his sperm to produce full siblings, court papers state. The doctor allegedly claimed the medical records were destroyed long ago, since the law requires records to only be kept for seven years.

Dr. Cline allegedly told the siblings he didn’t know when he “stopped using his own sperm to inseminate women,” the affidavit says. Still, the youngest of his fertility clinic offspring was born in 1986, prosecutors say.

“He told the siblings if he would have known that DNA would have come this far and this would have come out, he would not have done it,” the affidavit states.

“Dr. Cline thought he was just helping people have babies,” court papers added. “[He] apologized for what he did and said that since he has found God, he now knows what he did was wrong because he hurt a lot of people.”

One woman recorded a phone call with Dr. Cline in which he begged for her to keep the revelation quiet, court papers say.

The doc said Fox 59 was hounding him and that the news would affect his marriage. “He said his wife considers what he did adultery,” the affidavit states. “He asked [the woman] to help him by not telling the world of their secret.”

In the call, Cline allegedly said “he thought he was doing the right thing and was helping people with no other recourse.”

Four siblings filed complaints with the Office of the Indiana Attorney General in December 2014, the affidavit says. (In a statement, an AG spokeswoman said the office has not filed any formal action against Dr. Cline’s license, which is inactive.)

The attorney general then asked Cline for written responses to the allegations, prosecutors say.

In his responses, Cline stated he practiced under Indianapolis Infertility Inc. from 1979 through 2009, when he retired, and that his donors “were either resident doctors at various hospitals… or resident dentists specializing at the Indiana University School of Dentistry.”

Cline said he matched female patients with donors of the same blood type and physical traits as their husbands and did not treat single women, the affidavit says.

In the early 1980s, Cline claimed, he stopped using fresh semen and turned to frozen samples from Follas Laboratories.

“I can emphatically say that at no time did I ever use my own sample for insemination nor was I donor at Follas Laboratories,” Cline wrote, before accusing one female complainant of libel and slander.

But a subpoena sent to Follas Laboratories in February 2016 found no records pertaining to Dr. Cline or his clinic, prosecutors say. The lab did not act as a distributor of frozen sperm samples, court papers state.

In July 2016, a search warrant granted investigators to obtain a cheek swab from Dr. Cline for a DNA comparison to two women. The results, returned one month later, showed Cline matched the women by more than 99.9 percent.

The women, who have wished to remain anonymous in local reports, did not return messages left by The Daily Beast.

“I want to know every sibling that I have,” one sibling told Fox 59. “I don’t think that is ever going to be a possibility.”