Broadly speaking, the term "issue" refers to a person's lineal descendants.

Formally, California Probate Code Section 50 provides:

“Issue” of a person means all his or her lineal descendants of all generations, with the relationship of parent and child at each generation being determined by the definitions of child and parent. 

Often, an estate planning lawyer will provide that a bequest will go to a beneficiary's "issue" if that beneficiary doesn't survive. It's also important to remember that the term "issue" is also used for purposes of intestate succession and anti-lapse statutes. 

A Trustor also has the ability to broaden or narrow the definition of issue to ensure that the Trustor's estate planning documents properly reflect his or her wishes. Thus, a Trustor may wish to include adopted persons who were under a certain age at the time of adoption or to include stepchildren. (One may also exclude certain individuals.) 

Making a gift to a minor may be difficult for a number of reasons. The minor may not be legally able to manage the property that you leave for them. In addition, they may not be responsible enough to manage the asset for their long term benefit.

For some, making gifts to their minor children may be a technique to reduce the size of their estate for estate tax purposes. Whatever the reason may be, there are a couple of options for making a gift to a minor that may be suitable depending on your specific situation.

Trusts

Some people decide to use a trust as the primary vehicle for holding and managing property for a minor. The trust has the benefit of having a Trustee who can manage the trust asset and who may be granted the discretion to make distributions to or for the benefit of a minor child. This trust could be established for your child either while you're alive, or it can be set up at the time of your death.

One downside to using a trust, however, is that the cost of maintaining a separate trust for a minor child may be excessive in relation to the value of the assets held in the trust. 

California Uniform Transfers to Minors Act

Where the gift to minor person is relatively small, using a custodial account under the California Uniform Transfers to Minors Act (CUTMA) may be more attractive. Generally, the gift is held by the Custodian you select until the minor child reaches a specified age.

Figuring out the best way to transfer your assets to minor beneficiaries can be challenging. Most people grapple with the desire to provide for the child but not grant unfettered access in a way that would cause the minor to lose motivation in pursuing his or her own life goals. Estate planning lawyers can provide helpful insights on how to structure such a gift.

A basic function of estate planning is to make sure the people or organizations that you want to receive your property actually receives it, but have you really thought about how that would work? Would you just give a lump sum to your teenage son or daughter? If you left money for a charity, how would you know they are using it in the way that you want? What if a person you wanted to leave something to passed away before you--who would get it then? If you have a business, will your partners buy you out? Or, will your family join the business and work in it?

Some Basic Techniques

As a general rule, I think the "KISS" method works quite well in estate planning. (KISS = "Keep It Simple, Stupid") The more complications that get introduced to a distribution scheme, often the more failure points you may be introducing. That being said, there are some basic, tried and true techniques that work and are often good to implement. Here are some of them:

1. Leaving gifts to a young beneficiary in a trust that call for distributions at various ages. Or, if the amounts are rather small, utilizing "CUTMA" to hold the property for the beneficiary until he or she reaches a certain age.
2. Utilizing a marital trust to hold property for your spouse to give him or her lifetime enjoyment of those assets, but also ensure that specified beneficiaries (often children) will receive whatever is leftover.
3. Providing that where a named beneficiary fails to outlive you, the property going to that person will get distributed among his descendants. This is a commonly used provision where you want to benefit not just the beneficiary you've named, but also that person's family.

If you engage an estate planning lawyer, you will undoubtedly face one or more of these concepts depending on your situation (e.g., whether you are in a relationship or have children).