Well I don't know exactly how it was taught to you, so I can't say. But I definitely think kids do need to be taught these things. If two kids decide to start "experimenting", at least if they have a proper sex education they'll know how to stay safe, and the worst thing they'll have is a bad experience. If they don't know about the possible consequences of their actions, they could end up in all sorts of horrible situations. It's better to teach kids "wait til you're ready to have sex, but when you are, stay safe", rather than just tell them "SEX IS WRONG IF YOU HAVE SEX BEFORE MARRIAGE YOU WILL GO TO HELL".
Another thing is that sex needs to be destigmatised. Children shouldn't be taught that it's something horrible and wrong, but that it can be very beautiful, in the right circumstances. They also need to be taught that there is no shame in it. If a child is abused by an older relative and she's been taught all her life that "sex is wrong", her terrible experience will be compounded even further by a deep sense of shame, she will feel isolated, and there's very little chance she will tell anyone what has happened. If there wasn't so much stigma around sex, abused children would at least not feel like social outcasts, and they may have more confidence to speak up.
Oh come on, you can't tell me that that's evil, Hanna.
edit: just watched the video in rockzmom's post. Holy f*** that is disturbing.