Scientists have discovered why those mass produced tomatoes tend to be tasteless, and found a way to grow big tomatoes that are actually quite sweet and the process involves gene editing. So, what are the laws and ethics of the process - and could we see such crops in Australia? Guest: Dr Jonathan Webb, ABC Science Editor Brainteaser (answer in the audio): There are three in this sentence. This brainteaser contains six. How many can you find in this sentence?   For more of the latest science news, look for the science section on the ABC News website and sign up to a weekly email newsletter.