Nate Phelps, the son of Rev. Fred Phelps who helms the anti-gay Westboro Baptist Church, has called his father a “sociopath.”

According to St. Louis-based gay weekly The Vital Voice, Nate spoke to a 500-person crowd on Thursday at Clayton High School.

“I think he's a sociopath,” Nate said of his father. “I think that he fits that based on his inability to empathize with others, his calculated cruelty, and by laughing at the harm he causes. I've seen that growing up with him.”

Many of Nate's 12 siblings remain in the Topeka, Kansas-based church known for coining the phrase “God hates fags” and picketing at the funerals of fallen soldiers, because their deaths are the price America pays for its acceptance of “the sin of homosexuality.”

Nate described how he escaped his father's home: “I knew I was going to do it when I turned 15 or so. I bought a car when I was 17 – hid it – no one knew it was mine. [I] packed my stuff up and at 11:30 on the night of my 18th birthday, I backed it into the driveway and loaded it up and went inside. [I] waited for the clock to hit midnight and then I left.”

Nate now lives in Canada.