Doctors in China have spent 12 hours reattaching a 12-year-old boy’s genitals after his stepmum allegedly cut his penis and testicles clean off with a fruit knife.

The 12-year-old boy, whose name has not been given, is in stable condition, but doctors fear he may never regain full function of his reproductive organ.

The child living with his father in the city of Fuyang was reportedly attacked by his stepmother in their rental home on 3 March.

His dad returned home to find him severely injured, and took him to Fuyang People’s Hospital for treatment.

The boy, whose severed penis and testicles were carried to hospital in a bag, was eventually referred to the First Affiliated Hospital of Anhui Medical University.

The 11-year-old boy recovering from surgery. Credit: AsiaWire / AsiaWire/Australscope

Zhang Xian, the hospital’s head urologist, said the boy’s genitals were successfully reattached during a 12-hour operation lasting from 8pm to 4am the following day.

The boy has since woken up from surgery and remains in stable condition.

The medic said: “He went from hospital to hospital. It caused such a big delay.

“His genitals were cut clean off and brought in a bag.

For more on 7NEWS.com.au

“I’ve never seen anything so cruel. His penis and testicles were completely severed.

“The boy said his stepmum did it.”

The doctor reported that the boy would be able to urinate normally in the future, but that it would be “very difficult” for him to recover the “efficacy” of his organ.

The child’s stepmum, 32, who has not been named, is believed to be in police custody as an investigation continues.

The reason behind the alleged attack is still unclear.