woa - what's wrong with you? Kamasutra?
If your kids are at the age where they are curious about Kamasutra - then they will satisfy their needs NO MATTER WHAT.
Personally, I think if the child has come across the "WORD" and is curious - their question must be acknowledged and supplemented with a RESPONSIBLE answer.
That does not mean that - okay it's time to talk about Sex at an early age - it just mean that you can choose good vocabulary to make your kid understand without going into details.
*You are jumping to conclusion that any parents who choose to educate their kids, in their own ways about reproduction/drug/and all the bad things - is unethical? *
I think those parents are actual fulfilling their responsibility as an adult by answering the curious minds in a responsible manner - so the kids don't have to go out and get info from others/strangers - who might be a bad influence.
Really? That also makes me unethical because I have also chosen how to educate my kids.