A DAD has been arrested after DNA results revealed his step-daughter gave birth to a baby with a 99.9 per cent match to him.

Dustin Walker, 34, is accused of sexual abuse after the “traumatised” girl, delivered a child in their home in Muskogee, Oklahoma.

Mr Walker, the girl’s step-dad, and her mom Cherie Walker, 33, were arrested last week and initially charged with one count of felony child neglect following the baby’s birth on August 16.

The parents claimed they didn’t know the girl, who hadn’t been to a doctor in a year, was pregnant.

On Monday, their charges changed after a DNA test revealed the step-dad was a 99.9 per cent DNA match for the baby’s dad, The Muskogee County District Attorney’s Office told NBC News.

Mrs Walker was charged with enabling child sexual abuse, while her husband was charged with sexually abusing the girl.

In a statement, Muskogee County Assistant District Attorney Janet Hutson said: “This is one of the most if not the most serious child sexual abuse and neglect cases I have ever prosecuted.

“This child is traumatised. She’s been through a horrific ordeal. I mean, not only has somebody gotten her pregnant, but she gave birth at home without medical assistance, and this will be her life for the rest of her life.”

She added: “Each of the charges against both defendants are punishable by up to life.”

According to court documents, the couple were also charged with six counts of felony child neglect, including failing to supply proper medical care and supervision to the child when she was in labour.

The other charges relate to the treatment and care of their five children – aged, two, four, six, and nine – who were found to be “living in deplorable” conditions.

Cheryl Adkins, who lives next door, claimed the kids had “no running water” for the last two to three years.

Referring to the child’s pregnancy, she told 2News: “This is getting to me. They robbed her of her childhood.”

The children were pulled from their home on Tuesday where they were found with “no clothes on” and “living in dog feces”, court records said.

The kids’ grandmother, known only as Michelle A, claimed the conditions were down to the number of animals living in the family home, adding that the couple “try to keep it clean”.

When asked about the parents’ treatment of their children, she insisted they “love those children”.

She added: “They’ve made my daughter and my son-in-law a monster.”

The couple will appear in court on September 3.

It comes just days after Brittney Mae Lyon, 31, was captured weeping as she was jailed for sending disabled children to her sick lover so he could rape them.

The twisted carer earned the trust of parents who left their kids under her supervision by boasting she had studied child development.

But the San Diego woman was actually sexually abusing the girls – providing them to her boyfriend Samuel Cabrera, 31, so he could molest them.

In some cases, he filmed the horrific abuse on victimss as young as three years old and as old as seven.

The disabled children were autistic and non-verbal.