Please, all read this from wikipedia:
The term Indigo children originates from the 1982 book "Understanding Your Life Through Color," by Nancy Ann Tappe, a self-styled synesthete and psychic, who claimed to possess the ability to perceive people's auras. She wrote that during the mid 1960's she began noticing that many children were being born with "indigo" auras. Today, she estimates that 60% of people age 14 to 25 and 97% of children under ten are "Indigo."
http://en.wikipedia.org/wiki/Indigo_children
So it's just because of the dimensions moving thing that more and more kids are being born with much higher awareness than their parents or grand parents.