(CNN)Bill Gates made some eyebrow-raising claims about President Donald Trump on Thursday, saying he doesn't know the difference between two sexually transmitted diseases and that it was "scary" how much Trump knew about Gates' daughter's appearance.
Bill Gates describes interesting encounters with Trump
Taking audience questions about his interactions with Trump at a Bill & Melinda Gates Foundation meeting, the former Microsoft honcho said he first met Trump in December 2016. He told the audience that Trump had previously come across his daughter, Jennifer, at a horse show in Florida.
"And then about 20 minutes later he flew in on a helicopter to the same place," Gates said, according to video of the event broadcast by MSNBC late Thursday. "So clearly he had been driven away but he wanted to make a grand entrance in a helicopter.
"Anyway, so when I first talked to him, it was actually kind of scary how much he knew about my daughter's appearance. Melinda (Gates' wife) didn't like that too well."
Gates also said he discussed science with Trump on two separate occasions, where he says the President questioned him on the difference between HIV and HPV.
HPV stands for human papillomavirus and is defined by the US National Institutes of Health as "a group of related viruses" which is sexually transmitted and can cause some types of virus, warts and cancer. HIV -- human immunodeficiency virus -- is a sexually-transmitted disease which breaks down the immune system and can lead to AIDS.
"In both of those two meetings, he asked me if vaccines weren't a bad thing because he was considering a commission to look into ill-effects of vaccines and somebody -- I think it was Robert Kennedy Jr. -- was advising him that vaccines were causing bad things. And I said no, that's a dead end, that would be a bad thing, don't do that.
"Both times he wanted to know if there was a difference between HIV and HPV so I was able to explain that those are rarely confused with each other," Gates said.
CNN has reached out to the White House for comment.