I'm quite shy about kissing for two reasons, both of which are based on probability. First one is a sad story, I have an injury which means my neck can move this far to the right, but only this far to the left, which means the probability of me avoiding and nose to nose collision is only 50%. That's a problem of probability, but the second problem is to do with cancer, and again that's a disease of probability, because cancer occurs when your cells grow out of control and they form a tumor or a mass, and the control mechanism is embedded within your DNA. Now if there's an alteration to that mechanism through damage or mutation, cancer arises. But what does that got to do with kissing? Well there's a virus known as the Epstein-Var virus, which is spread through saliva, and it affects an error the body known as the nasa farinks. So when you laugh and rice comes out of your nose, the region the rice passes through from mouth to nose, that's the nasa farinks right there. And the virus affects this region, and it can't enter the cells directly and affect the DNA, but there's a more subtle mechanism. By infecting this it kills the cells, and we need to reproduce them, and every time we do this a small but finite chance that there's an error in the copying of our DNA, and if that error occurs in the control mechanism then the result will be a cancer. Now for people from South China we have a 25 times higher chance of getting this particular cancer from this virus than any other country in the world, which means that when you say, because I'm worth it, I'm actually doing the calculation. It's quite a difficult one, I'm trying to use a dating friendly technique, so I can use for example a nasal swab, and plug that into a portable PCR machine, which can detect the presence of viral DNA, but the problem is it's only 95% accurate. So if I were to test and kiss everyone in the front row, chances are one of you is going to give me a deadly infection, so testing really isn't effective, and the only way for me to mitigate the risk is to modify my behavior, so I'm sorry to disappoint you. Now this is one example of many of the probabilistic diseases that are a huge global burden today. Think about cancer, stroke, heart disease, all of these are probabilistic diseases and the multifactorial, which means the error of this wonder drug that cures a single disease, that's really over. The best method that we have of dealing with these probabilistic diseases is communicating with patients and with the public specifically about the statistics and risks that you all take in your day-to-day behaviour. Ladies and gentlemen, when you go home tonight out of sympathy for my kissing plight, I encourage you please to think about your own risks and own behaviours, and above all what comes to kissing, make sure he or she is worth it. Thank you very much. So what made you choose kissing? Was it a desire to kiss everybody in the front row? No, I'm a little bit of, I think it's one of these examples of probability, which I can do more in Europe than in Hong Kong. We're quite a conservative culture, for example I couldn't invite you out for a cocktail and an nasal swab in Hong Kong, but if you're interested I have one available. 9.30? Sure, yeah, sounds good. This was very romantic. So you are a doctor, you are an author of books, so what do you think will be your future career? I think being a doctor really is involved in being a science communicator to patients. I also do some lecturing for students and that's some communication. The most important thing is I have a Chinese mom, so who might need to explain a lot of things that she reads and she says, oh okay, Chris I've read that they can give you cancer, that they can cure cancer and these kind of things. I think science communication hopefully will be a big part of what I do in the future. Thank you. Hook her up, please, for Dr Christopher C.