A Pennsylvania, USA, woman has been arrested on charges of rape after she allegedly had sex with her 17-year-old son, World Wide Weird News reports.

Williamstown Police said that the teenager told investigators that he forced his mother to have sex with him by blackmailing her.

Police received a report about the sexual encounter shortly after it occurred and swiftly arrested the woman, believing the boy to be a victim in the case despite claiming he blackmailed his mother into having sex with him.

The woman has been placed on bond while the boy has been taken a to a juvenile home and is being treated for trauma associated with the incest.