UNNAMED DAD, apparently with mental illness.
http://www.sandiego6.com/news/local/Father-Hears-Voices-and-Slashes-Sons-Forearms-149389085.html
Father Hears Voices and Slashes Son's Forearms
Officers later arrived and took the father into custody and was transported to a local trauma center where he will be treated before being booked into County Jail.
The child was taken to Children's Hospital for treatment.
The father will be booked for child abuse and assault with a deadly weapon. The Child Abuse Unit is investigating.