Look. It may not necessarily be harmful for an adult and child to have sex. But that's not a good reason to make it legal. Use your brain. If adult-child sex was legalized that would open the door to so much sexual exploitation. Children will start prostituting themselves and adults will pimp out their own children. All of this would go down secretly and away from the view of the law. No matter what you say there WILL be an increase in child exploitation and sex trafficking if this was legal.
A parent can easily groom a kid into lying to police to protect the business. This sick shit would be going on world wide.
Childhoods will be destroyed because of this!
That's why children shouldn't be able to consent with adults. Because children will quickly sell themselves and adults will force kids to sell themselves and it will be nearly impossible to stop.