I should have worded it differently

Today in Biology my professor was talking about genetically modified produce. She said that if we've eaten corn recently, there's a good chance that it's been genetically modified. She also was talking about meat having been genetically modified and the high possibility that we've eaten some of that, too. Not much was covered on it outside of "This is why it's done..." and then she stated, "The benefits outweigh the risks." I wrote that statement down, and started thinking. After a minute or so, I raised my hand and said, "Wouldn't you agree that not enough time has passed to truly determine that the benefits outweigh the risks?" to which she replied (hastily, I might add), "Yeah, you're right. I shouldn't have said that." She floundered a little bit a little more. I swear I didn't mean for it to sound rude, and I'm hoping that she's not too angry that I pointed something out to her regarding the lack of solid evidence proving her statement to be true. I swear, I feel more and more like the one person in the class who's a know it all. I just watch Discovery Channel a lot. And I read a lot.