Police are asking the public for help in locating John Adam Greene, 29, of Hamilton.
He is considered to be dangerous and may be armed, police say. The public should not approach him.
Anyone with information is asked to call police at 911 or Crime Stoppers at 1-800-522-8477.
Police were called around 3:45 p.m. on Saturday to an address on Sanford Avenue where the incident happened, Staff Sgt. George Narozniak told CBC Hamilton.
The child and the family are now safe, Narozniak said.
He would not elaborate on the identify of the child or the address of the home.
Greene is known to police, Narozniak said.
Greene faces charges of abduction, aggravated sexual assault, sexual interference, assault causing bodily harm and threaten death, police say.
The investigation is ongoing.