A convicted sex offender who raped a Michigan woman when she was only 12 years old has now been granted joint custody of his victim’s 8-year-old son, according to a report.

Christopher Mirasolo, 27, was awarded joint legal custody — and shared parenting time — with his now-21-year-old victim after DNA testing established the child’s paternity late last month, the Detroit News reported.

The victim’s attorney, Rebecca Kiessling, is seeking protection for both the woman and her child under the federal Rape Survivor Child Custody Act, she told the outlet.

“This is insane,” Kiessling said. “Nothing has been right about this since it was originally investigated. He was never properly charged and should still be sitting behind bars somewhere, but the system is victimizing my client, who was a child herself when this all happened.”

Kiessling has filed objections with Sanilac County Circuit Judge Gregory S. Ross, who made the order, according to the report.

She claimed Ross had disclosed the victim’s address to Mirasolo and ordered the rapist’s name to be added to the boy’s birth certificate — without the victim’s consent or a hearing, according to the report.

The Detroit News was unable to reach Ross for comment.

Kiessling told the outlet that the victim and her sister slipped out late one night in September 2008 to meet a boy when the boy’s older friend, Mirasolo, asked them if they’d like to go for a ride.

Mirasolo ended up holding them captive for two days in a vacant house before he released the older sister in a park — and allegedly threatened to kill both girls if they ratted him out. He then raped the younger girl, according to the report.

He was arrested a month later when the pre-teen became pregnant. He was sentenced to one year in county jail but only ended up serving six-and-a-half months so he could care for his sick mother, Kiessling said.

“[My client] and her family [were] told first-time sex offenders weren’t sent to prison because people come out worse after they go there,” Kiessling told the Detroit News.

Mirasolo was arrested for a second sex assault on a teenage victim two years later — for which he only served four years in prison, according to the report.

It wasn’t clear how much time Mirasolo would spend with the victim’s son, Barbara Yockey, his attorney, told the Detroit News.

“Chris was notified of the paternity matter and an order of filiation was issued last month by the court saying he had joint legal custody and reasonable visitation privileges,” she said. “He never initiated this. It was something routinely done by the prosecutor’s office when a party makes application for state assistance.”