From the cpsia guidelines. I'd market them in adult sizes only. If someone gives you a size (unless it's really small) how are you to know who is the ultimate user.
What is a children's product?
A children’s product is one designed or intended primarily for children 12 years of age or younger. Toys, clothes, furniture, books, jewelry, blankets, games, CDs/DVDs, strollers, and footwear may all be considered children’s products.
In determining whether a consumer product is “intended primarily” for a child 12 years of age or younger, the following factors will be considered:
A statement by the manufacturer about the intended use of the product, including a label on the product, if such statement is reasonable.
Whether the product is represented in its packaging, display, promotion or advertising as appropriate for use by children 12 years of age or younger.
Whether the product is commonly recognized by consumers as being intended for use by a child 12 years of age or younger.
The Age Determination Guidelines (pdf) issued by Commission staff.
If a product is intended for adults or for general use by consumers of all ages, then it is not intended primarily for children. Products marketed and priced in a manner that would not make them appropriate for use by a child would also not be intended primarily for children. An example would be an expensive telescope -- because it is sold for general use by all ages, it is not a children’s product even though it can be used by a child on occasion.
