A 17-year-old father face charges of child cruelty and causing grievous bodily harm over leg and arm fractures to his baby son.
Llandudno youth court magistrates were told the baby's injuries were found after his mother took him to hospital at Llandudno at the end of February.
Julia Galston, prosecuting, said the child, born in December 2009, had an unexplained injury to his right arm.
No pleas were entered at the hearing and the father was remanded in custody.
The father also faces unrelated charges of aggravated vehicle taking and assault.