I can see a good argument for the age of criminal responsibility being lower (12) than for sex (16-18 depending on jurisdiction) because the competency bar you need to clear is lower. I know there's a host of regulatory bloat, but at a basic level for not becoming a criminal it's "Don't initiate violence or steal". Not very complicated. Whereas for sex it's understanding how to identify virtue in a potential partner, understanding how to balance reason vs hormones, understanding the marriage and teamwork required to raise a child, understanding how to use birth control effectively, etc. It's similar to how the requirements for a basic drivers license are lower than a commercial drivers license because changing lanes in a Civic is a whole lot less complex and risky than doing the same in an 80,000 lb semi. Now that I look at it that way, I think there's a pretty good argument for raising the age of consent even higher because I'm not very confident in 18 years to be able to accomplish that. Maybe 25? Shit, maybe even a mandatory "are you a fricking retard" test to ever be able to give consent because I know grown adults who can't accomplish that level of partner evaluation at 50.