HSV-1 is the most commonly acquired form of herpes and is typically spread through a social kiss such as that of a family member. Due to the lack of immune response in children, new HSV-1 infections typically occur in childhood.
Update: "Recent research indicates that HSV 1 is probably not more easily acquired than HSV 2. And now, the average age of acquisition of HSV 1 is in the teens, rather than childhood" according to a licensed healthcare provider.

By the time that child reaches adulthood, they will be one of 50% of American’s living with HSV-1. By the time a person reaches the age of 50, they will be one of 80-90% of those who carry HSV-1.

damnn .. look around. i bet 1 out of every 2 people around you has herpes && doesn`t know it.