Bill Gates recently helmed a Bill & Melinda Gates Foundation meeting with staff, and per the Guardian, he offered some anecdotes involving President Trump.

In the footage aired Thursday night on MSNBC, Gates noted that when he first met Trump in late 2016, it was “kind of scary” how much Trump seemed to know about his adult daughter Jennifer’s appearance.

“Melinda didn’t like that too well,” he said. He also noted that in that 2016 meeting, as well as in a subsequent one in March 2017, Trump threw out a question that actually threw Gates during a discussion about vaccines.

“Both times he wanted to know if there was a difference between HIV and HPV,” Gates told his audience. “So I was able to explain that those are rarely confused with each other.”

Trump apparently isn’t the only one who may have harbored uncertainty about the viruses: The Guardian points out the UK’s National Health Service website features a dedicated page with the question “What’s the difference between HPV and HIV?”

Still, jokes flew online about the president possibly not having a handle on this.

“Guys, we could probably get him to stop watching Fox and Friends by telling him it has HDTV,” one Twitter user snarked.

One other Gates anecdote that drew laughs: “When I walked in, his first sentence kind of threw me off. He said: ‘Trump hears that you don’t like what Trump is doing.’ And I thought, ‘Wow, but you’re Trump.'” (Where the two men rank on Forbes’ billionaire list.