Holy Angels Catholic church organized the all-day event, which started with a revival at 9 a.m.
At noon, the "Let Us Grow Up" march was scheduled to begin on East Oakwood, followed by a rally from 1 p.m. to 5 p.m.
Chicago 4th Ward Ald. William Burns, clergy and activists were expected to participate.
Fathers and sons were planning to hand out flower seeds, a symbolic gesture to let the sons grow up.
