A man who impregnated his biological daughter and was reportedly planning to marry her is facing incest charges. The man's daughter, who is now the mother of a baby, is also facing similar charges.

Steven Pladl, 42, of Wake County, North Carolina had given up his daughter Katie Pladl for adoption as a baby but when Katie turned 18, she got in touch with her parents through social media.

In August 2016, Katie started living with her biological parents and their two children near Richmond, Virginia. Her parents, however, got separated three months later, WNCN television station reported.

According to Steven's wife, who has not been named, her husband used to sleep on Katie's room floor in the months before she had moved out.

According to the arrest warrant, Steven's wife read in one of her children's journals that Katie was pregnant with her father's baby in May 2017. She also came to know that Steven had even told his other children to call Katie their stepmother.

When his wife confronted him, Steven allegedly confirmed that he had impregnated their adult daughter and that they were planning to get married.

The pair later moved to Wake County and in November 2017, a warrant was issued for their arrest.

When they were located, officers discovered a baby boy who was about four-months-old, WNCN reported.

Both of them were held at the Wake County Detention Center pending extradition to Virginia. They are charged with incest with adult, adultery, contributing to delinquency.

According to court records, Steven was released on a $1m bond while Katie remained in jail.

The two would make their first court appearance on Monday (5 February).