Originally Posted By: Wikipedia
While Kinder eggs have been available in Canada since 1975, the product has never been allowed into the US for at least several reasons. In 1993 the Ferrero Group (the maker of Kinder eggs) applied to have the eggs sold in the USA, but was turned down because of a prohibition against having an inedible item inside an edible object. More recently, the US Consumer Products Safety Commission determined in 2008 that the product did not meet the small-parts requirement for toys for children under the age of three, creating a choking and aspiration hazard in young children.

Interesting. Never knew there was a specific ban on having non edible items inside food. Somehow McDonalds is exempt from this :-)