Re Mrrzy's comment that 14-year-olds wouldn't be able to sell their bikes w/out parental consent, minors are considered legally incompetent to contract (buy or sell) w/out parental consent, except when the contract involves the necessities of life. This law was apparently intended to keep children from buying expensive, unnecessary items which they then could not legally return; but technically it would apply to selling also, so that if a child sold his bike for a dollar, the parent would have the right to negate the deal and repossess the bike. You may feel a 14-year-old has the right to make such a decision; on the other hand, do you want umpteen banks sending him/her credit cards? It's bad enough that 18-year-olds are bombarded with them!
Regarding special Mormon underwear, my information is that these are called "sacred garments". I've never actually seen any, but I understand they're somewhat similar to your summer-type union suit (short-sleeved and short-legged). Anyone who has actually glimpsed the sacred fabric, please enlighten our darkness!