When parents of young chldren draw wills, a chief concern is who will bring those children up, if the parents die. The most obvious choices may, on reflecton, be the wrong ones.

And even when a guardian is chosen, a legal hiatus may arise during which time there is no formally able to make decisions about the childrens care and welfare.

First, the matter of choosing a guardian: Young parents tend to think first of their own mothers and fathers or the children's grandparents. But deep in their hearts, many grandparents would not be overjoyed to start the child-rearing cycle all over again. Also, by naming older guardians, you're setting your children up to lose a second set of parents.

Brothers or sisters come next to mind, if they're old enough to be responsible for children. In many families, this works well. On the other hand, you may thoroughly disapprove of the way your brothers and sisters raise their own children.

There's no real need to put the blood tie first in selecting a guardian for your children. Their future may be better served by seeing that they stay in their old neighborhood, perhaps in their own home, under the care of people they know well and who share you attitudes toward child-rearing.

This may mean asking a close friend to act as guardian. Talk the matter over with the friend, to be sure that he or she is not taking on the job reluctantly. Also, tell the prospective guardian roughly what provisions would be made for the children's support.

As your children grow older, they'll have their own ideas about where they'd like to live if anything happens to you. Sometimes, an older child becomes an ideal guardian for a younger brother or sister.

In the case of separation or divorce, the noncustodial parent becomes the guardian if the custodial parent dies. You usually can't do anything about this by naming a different guardian in your will. But sometimes, the noncustodial parent is just as glad to leave the child where he is -- perhaps with a step-parent or other relative. Naming a guardian at least indicates you wishes.

Unfortunately, naming a guardian in your will doesn't always do the job. For example, what happens if no one can find your will? What if your will is invalid (as so many handwritten wills turn out to be)? What if someone in the family challenges the will? During that interim period, no one is formally in charge of the children.

Normally, that won't particularly matter. Someone will take care of the children until the matter is settled. But what if there's an emergency? If one of the children, say, has to have an appendectomy? Many doctors and hospitals are reluctant to act without legal authority, which only a guardian can give. It might be necessary to get court permission for an operation.

And another problem: What if the child's parents dont't die, but instead become seriously disabled by an illness or an accident? Court hearings would be necessary to designate a guardian for the children.

Under the uniform probate code, in effect in many states, parents may name a temporary guardian -- for example, to make decisions about the child's welfare if the parents are ill or out of the country.But this authority lasts only six months at a time.

New York lawyer Edward S. Schlesinger recently dug up a 1757 provision in New York law, which provides for a "deed of guardianship." It seems to fit today's needs so well that the people involved with the uniform probate code are considering recommending it to all states.

A deed of guardianship is separate from a will. Anyone can file the deed at the county courthouse after the parents' death, and the guardian becomes immediately responsible for the children, no matter what wrangles surround the will.

The New York law isn't clear as to whether such a guardian can act in case of a parent's disability, Schlesinger says. That's an important hole that should be plugged if any other state adopts the concept.

The risk to children during a period of legal limbo is something that wouldn't occur to most parents. But that's what lawyers are paid to worry about. "Serious things do sometimes happen," Schlesinger says. The probate laws should close these loopholes, and New York's deed of guardianship may be the model that other states should use.