UTMA (Uniform Transfers to Minors Act), available in 48 US states*, is a provision whereby an adult can transfer wealth to minors.
In most states, the minor doesn’t come into possession of the assets until the age of 21. In some states, the minor must take possession of the assets at age 18. Check with your tax advisor to learn the UTMA regulations in your state of residence.
With the Hard Assets Alliance, UTMA accounts are free and easy to set up. It only takes a few minutes to set up, and you can usually start the buying process within 2 business days.
If you already have an account with the Hard Assets Alliance, you may use your existing username and password to set up the UTMA account, so that all of your accounts are controlled under a single login.
As a custodian of that account in the minor’s name, you may buy on their behalf, but you cannot take possession of the metals. The metals are, after all, being bought for someone other than you.
* UTMA regulations have not been adopted by Vermont and South Carolina as of the last update of this question.