Joe Biden, the 2020 Democratic candidate, can welcome a sixth grandchild into his family after a DNA test confirmed that his son Hunter was the father of an an Arkansas "Baby Doe."

The new family member marked a second landmark for Biden on Wednesday, who also turned 77.

Testing found “with scientific certainty” that Joe Biden’s son fathered the child, according to a motion filed Wednesday. He “is not expected to challenge the results of the DNA test or the testing process,” the filing said.

“Baby Doe’s paternal grandfather, Joe Biden, is seeking the nomination of the Democratic Party for President of the United States of America (he has already filed for the March 2020 Arkansas primary). He is considered by some to be the person most likely to win his party’s nomination and challenge President Trump on the ballot in 2020,” the filing added.

The court document also said members of the Biden family were eligible to be protected by Secret Service.

Biden, 49, agreed to take the paternity last month after 28-year-old Lunden Roberts claimed he was the father of her one-year-old child. Biden has publicly denied he was the father, but Roberts said Biden had admitted otherwise to her in private.

The name and gender of the child in question is not known. The Biden campaign did not immediately respond to the Washington Examiner's request for comment.

Hunter Biden is the father of three daughters — Naomi, 24, Finnegan, 19, and Maisy, 18 — from his 24-year marriage to Kathleen Buhle. The two divorced in 2017. Joe Biden has two other grandchildren, Natalie, 15, and Robert "Hunter" II, 13, whose father was Beau Biden, who died in 2015.

He has since dated the wife of his late brother, Beau Biden, and married Melissa Cohen, a filmmaker from South Africa, earlier this year.

Roberts's attorney, Clinton Lancaster, said that she wants to avoid the media spotlight.

“She really does not want this to be a media spectacle. She does not want this to affect Joe Biden's campaign. She just wants this baby to get financial support from the baby’s father,” Lancaster said about why Roberts filed a petition for paternity and support.

Roberts attended college at Western Illinois University, playing for the college’s basketball team before transferring to Arkansas State University, where she graduated in 2014 with a degree in interdisciplinary studies.

She was living in Washington, D.C., and Virginia from 2015 to 2018, according to public records, which would have been the time when the child was conceived.