n. The perceived notion that children of all ages are performing activites, particularly playing with toys, traditionally seen as being suitable for older children.
American Girl, the line of dolls from different historical eras, has positioned itself as a brand that helps girls hold on to little-girlhood for a bit longer. … Even some girls see American Girl dolls as an antidote to the K.G.O.Y. poison. "They look like regular girls-they don't have all that makeup on like Barbie or Bratz" is how Annie puts it.
—Margaret Talbot, “Little Hotties,” The New Yorker, December 04, 2006
Kay Hymowitz, author of Ready Or Not: What Happens When We Treat Children As Small Adults, accuses the marketing industry of deliberately sexualising girls for profit. 'Marketeers make it sound like "KGOY" is just a fact of nature. The truth is, they have played a central role in making it happen,' she says.

'They want to sell products; they know kids who are independent and "empowered" are more likely to tell their parents to buy those products and that the way you seize kids' attention is to make them feel older, more glamorous — and sexier.' At the 2003 Kid Power conference for marketeers to children and teens in London, organisers instructed attendees in how to harness 'the power of word of mouth', how to ensure their products are 'the talk of the playground', how to get past 'the gatekeeper' (Mum and Dad), and to be aware of the influence of 'pester power'.
—Tess Stimson, “Brazen Bratz,” Daily Mail, October 19, 2006
1995 (earliest)
The industry is beset by a phenomenon dubbed by industry insiders as KGOY, or Kids Getting Older Younger. Teddy bears, spinning tops and dolls are being gradually squeezed out of a world where by the age of 11 children are turning from building blocks to personal computers for fun.
—Ardyn Bernoth, “Playtime ends for toy industry,” The Sunday Times, June 25, 1995