My biggest issue with this type of thing is the age factor. Who decides what the age should be to have sex and why does it change based on location? Who makes the decision that the age of consent is 16 (or what ever)? why 16? Like what was mentioned before, its ok for a 14 year old to have sex with another 14 year old, but not an 18 year old?
You can even flip it. What makes an 18 year old mature enough to have sex? Because someone decided that 18 is the age you become an adult? so anything under that age is not an adult.