A punch line from the movie "Ted" has people with Lou Gehrig's disease crying foul.
"From one man to another, I hope you get Lou Gehrig's disease," says Mark Wahlberg's "John" -- a quip some patients say crossed a line.
"I didn't expect to go to a movie and sit with an audience laughing at the expense of people with ALS," said Randy Pipkin, who was diagnosed with Lou Gehrig's disease in 2005. "I think the message this film sends out is a huge slap in the face to people dying from this horrific disease."
Lou Gehrig's disease progressively robs people of their ability to move, speak, eat and breathe. There is no cure.
"This line from Ted is something that never should have been said much less survived the editing process for a major movie release especially as a punch line for a comedy," Jeff Lester, an ALS patient from Lebanon, Mo., wrote in an open letter to Wahlberg and "Ted" writer Seth MacFarlane posted on Facebook.
MacFarlane is famous for his boundary-pushing humor. But Lester, a self-professed MacFarlane fan, says the punch line went too far.
"When you wrote or said, 'I hope you get Lou Gehrig's Disease,' were you thinking how funny it would be for my children to hear when they have friends or classmates repeat this line?" he wrote. "No it must be meant for my mom to giggle at the fact she has lived the last 18+ years with the knowledge that she will probably outlive her child."
MacFarlane and Universal Studios did not immediately respond to ABC News' request for comment.
"Ted" scored $54 million at the box office last weekend, and the offensive punch line has been making the rounds on Twitter ever since.
"We just want to stop this alarming trend before it becomes too widespread," Traci Bisson of the ALS Therapy Alliance, a Boston-based advocacy group, said in a statement. "We want to make it clear that ALS, or Lou Gehrig's disease, is not a laughing matter for people and families suffering from this life-threatening illness."
Lester said he condemns MacFarlane for writing the line and Wahlberg for speaking it, but added, "From one man to another, I hope you or anyone you know or love NEVER GETS Lou Gehrig's disease."
Today marks the 73rd anniversary of Lou Gehrig's famous farewell speech.