A scheduled speaking engagement by 19 Kids and Counting star and conservative activist Josh Duggar has been canceled in wake of recently unearthed allegations that he molested five underage girls when he was a teenager, marking the latest career setback for the eldest child in the famous reality show family.

The 27-year-old had issued an apology without addressing the accusations, which were described in a 2006 police report detailed in In Touch magazine and later, Fox News' FOX411. The scandal has spurred TLC to pull episodes of 19 Kids and Counting, which aired in reruns following its recent 10th season finale, off its schedule. The future of the popular series remains unknown.

Josh was scheduled to be a keynote speaker at one of the Teach Them Diligently Christian home-hchool conventions in the city of Sandusky, OH, which runs between May 28 and May 30. His parents, Jim Bob Duggar and Michelle Duggar, homeschool their children at their house in Arkansas.

"Yesterday, we heard the completely unexpected news regarding Josh Duggar," convention officials said in a public letter to supporters, shared on the group's Facebook page on Friday. "Since then, Josh Duggar has withdrawn as a speaker at Teach Them Diligently in Sandusky."

"While we could fret or argue over what is truth and what is gossip in the recent media reports, we would rather change the focus for a moment to what God has in store for the families that will be arriving on Thursday for Teach Them Diligently in Sandusky, OH," the letter said.