Katheryn Deprill posted this plea on the social network in early March: "I want her to know that I am not mad at her for what she did, however I have so many questions to ask her and also to start a relationship with my biological mother."
"Please help me find her by sharing my post," she added. "Maybe she will see this."
Her mom did see it, and the two were reunited Monday with a tearful hug.
An attorney for Deprill's mother, who helped arrange the meeting, said the mom was only 17 when she left the newborn Deprill in that Allentown, Pa., bathroom.
She had been raped while traveling abroad, and knew she couldn't take care of a child. She acted before her parents could find out she was pregnant.
"She left the baby in a location where the baby would be found and cared for," the attorney said. "She kissed the baby on the forehead ... and left."
Deprill was "super excited" to meet her biological mom.
"She left me somewhere she knew I'd be found. She did not want to throw me away," she said.
As for Deprill's goal of starting a relationship with her mother, it looks like that's going to happen, too. Her mom wants to be involved in her life, and they're making plans to meet up again.