Oh man, if Edward Jenner, the father of vaccinology, was alive today, he would get crucified over his discovery of the smallpox vaccine.

"What? Did you just scrape some cow's tits and inject fluid into a boy? No control? Where the ethics approval?"

And that's probably in the Top 10 of largest advancements in medicine of all time. Luckily he did it all before the existence of armchair keyboard warriors.