wow, lots of people here seem to be mis-understanding a lot of things.
First off, the age of consent is there to PROTECT young people from abuse, having an age of consent too low or non existent makes it much easier for people to then take advantage of young people. I won't go into detail on specifics but that is it's purpose. If the age of consent is say, 16, and a 17 and 15.5 year old have consensual sex, the police will not come running to your door and arrest you. Having consensual sex with an underage person is not akin to rape, because it is consensual. The age of consent is currently used as a guide, in the UK it is 16 as at 16 a person is able to leave education, get a job and sustain a family if need be. In many other countries legal work status and many other factors contribute to the current age of consent.
As a summary, it comes down more to "at what age can a person theoretically sustain a family" as to the actual law on the age of consent, and people using their heads and saying "17 and 15 isn't that bad, 25 and 11 probably means I should get the police involved". At the end of the day some people get interested in sex much earlier than others, decades in some cases, and people are always going to have sex under the age of consent. It always comes down to people being sensible and careful in all areas of life.
Just for information, I first had sex when I was 2 weeks away from 16.
Also for random facts, the lowest age of consent in the world is 9 in yemen (if married)
- source: wikipedia
Also, no stupid "this is sick stuff" replies please, people who can't post sensibly tend to get ignored or get counter-troll comments.