Update (5:37 p.m. EST): Cain concludes the press conference after his explanation of the allegation by Kraushaar. Live feed is over, but Twitter storm continues.
Update (5:35 p.m. EST): "I can only recall one thing that I was aware of that is called sexual harassment... one day in my office at the National Restaurant Association, I was standing with Ms. Kraushaar and I gestured like this (brings his hand up to his chest), 'you're the same height as my wife. She comes up to about here.' " He says his lawyer says that's the gesture that infuriated Kraushaar."
Update (5:33 p.m. EST): Cain says there's a possibility he might remember Bialek, just as he said he forgot the settlement with Kraushaar. "But I happen to think it's a remote possibility ... I seriously doubt I'm going to have an 'aha' moment later."
Update (5:31 p.m. EST): CNBC's Carl Quintanella tweets: "At the airport, where the sound of Herman Cain discussing sexual harrassment is blaring over a gate full of 10 and 12-yr-olds."
Update (5:26 p.m. EST): Cain says the allegation by Karen Kraushaar, who went public on Tuesday was "baseless," which he supports by pointing out the National Restaurant Association made a settlement with her.
Update (5:20 p.m. EST): Cain says "of course I'd be willing to do a lie detector test ... if I had a good reason," in response to a question by CBS News's Steve Futterman. But he says he'd need a good reason to do it. "I believe a candidate's character should come under a microscope, but with facts, not accusations."
Update (5:15 p.m. EST): Cain says he's not dropping out of the race. Like he told ABC News's Jonathan Karl earlier on Tuesday, he said he didn't remember Bialek at all. "These charges and accusations I absolutely reject. They simply didn't happen," he said. "I tried to remember if I recognized her and I didn't. I tried to remember the name and I didn't."
Herman Cain is scheduled to hold a press conference at 5 p.m. EST. He is expected to address the recent allegations from a number of women -- including Monday's claim by Sharon Bialek -- that he sexually harassed them. We'll be providing updates as the action gets underway, but you can also follow along on the live broadcast, below: