Relatives say they last saw Ryleigh Gnoski and her newborn son, Armoni, on Tuesday when the two left their home on the 8700 block of Marsden Street in the Holmesburg section of the city.
"I'm worried sick over my great-grandson. He doesn't deserve this. He needs to be safe," said Ryleigh's grandmother, Kathleen Gnoski.
Ryleigh's father, Peter Gnoski, said his daughter left with almost nothing for the baby.
"When she left, she didn't really take nothing for him. No diapers, no nothing," he said.
Family members say there was an argument before Ryleigh left home.
"She wound up walking out the house. Walked down the path and sat on the walk crying, waiting for someone to pick her up," her grandmother said.
The family reported Ryleigh and Armoni missing the following day. Philadelphia police said Ryleigh is known to spend time on the 2600 block of South Bouvier Street in South Philadelphia.
"That's where the so-called baby daddy is and them two are always together," her father said.
"Best case scenario would be Ryleigh getting the help that she needs and for us to take care of that baby and give that baby the life he deserves," he added.
Anyone with information can call or text Philadelphia police at 215-686-TIPS (8477) or submit an anonymous tip online.