bags, children sexually abuse other children, too. but i am with you in that preventing sexually mature beings from mating does seem unnatural.
i suppose another point to consider is that the age of consent for sexual activity varies from country to country - in spain it was 12, and may still be 12 for all i know.
when i was young i was told that in the past people became sexually mature at earlier ages because their lives would be shorter and they needed to breed early to keep the species going. my grandma's friends were 14-17. now, we have food and healthcare and girls hit puberty any time from about 9.
our view will be coloured by our socialisation, through education, media and experience.
also, isn't the age of consent about protecting property, not protecting young people? wasn't it brought in to protect the wealthy of young heiresses, who were being 'seduced' (or raped) to shame them into marriage with unsuitable men? or was that just a story put around?
i don't like the idea of children having sex. i think that's my sticking point. they're children.