Q: My husband and I have concluded that our marriage is over, and we plan to divorce soon. Naturally we are quite concerned about the impact such a move will have on our 16-month-old daughter, a very even-tempered, merry little soul.

We're both quite fit and loving parents and plan to live within several miles of one another. What are your thoughts on joint custody--where she would have, in effect, two homes? Is this arrangement too confusing to a child her age?

A: There probably is no trauma as tough on a child--or her parents--as divorce, except death. You want to be sure you've tried every possibility to save the marriage, including the painful year or two of counseling it takes to rescue what you once had or make you realize it wasn't there at all.

If the marriage can't be stabilized, your child will be helped most by good custody arrangements. They come in all sizes and shapes--just like families. But if they're right for you and her dad, they'll be right for her, too.

It isn't easy to find the right solutions now. Custody calls for creative thinking and sometimes more problem-solving than you ever have in marriage. The very tension that causes the divorce may interfere with the most rational plans. In fact, there will be times when any custody arrangement will take your best manners and a great deal of perseverance to keep it going. This is especially true with joint custody, when you usually see so much of each other while the wounds are fresh. It works best when the parting is fairly civil.

Joint custody is also called co-parenting, and this usually means an equality in parenthood that you may not anticipate. In a situation where parents have equal time with their child, they also have equal responsibility: for the carpools, the teacher conferences, the doctor visits, the shoe-shopping. They have equal responsibility for the financial support, too, usually proportionate to their income. This has its positive side. The investment in their child, both in time and money, usually makes both mother and father feel prouder of their ability to parent. They feel closer to their child.

On the negative side, joint custody is more costly (since both parents must live in larger quarters to accommodate their child) and more complicated. Plans must be fine-tuned to make sure the exchange goes smoothly.

Your daughter probably will accept the backing and forthing better than you. You have to realize that children spend so much of their time concentrating on their parents that they understand and accept the finest, most subtle distinctions between them--in logic, in expectations, in behavior. It won't even be too confusing to your daughter, as long as she is transferred on a reasonably fixed schedule. Even if it varies in a predictable way, she will feel comfortable about it, for children have a sense of order, long before they can read and tell time. It's the uncertainties that are upsetting.

Your daughter also needs to feel welcome in both places, with a nook to call her own, and books and toys. There should be enough supplies--and attention--to keep her relatively happy in both places, but they shouldn't be duplicated. Her teddy and her magic blanket can travel with her, but it would be contrived and stultifying if she had identical possessions in both places, and it would teach her to be manipulative, too. Every child occasionally tries to pit one parent against the other. And when the parents divorce, the child is likely to see the differences more clearly and will try to capitalize on them, claiming that one parent or the other gives them this or allows that. You'll want to avoid that, and you can if both you and your husband accept each other's differences as a parent. When you are secure enough in your separate identities, your child will be her own person in each setting too.

The toughest part of joint custody is down the road a bit. It's the reason why many of these arrangements dissolve. Even though you live nearby now, statistics predict both you and your husband probably will remarry. Then four adults have to agree to live and work in the same vicinity. In these days of high mobility, this isn't easy. It's quite possible for a child to live for six to 12 months in one home and then transfer to another that's across the country or even the ocean. The transfers, whether weekly or yearly, work best while the child is young.

Any shared custody is tough by the junior high school years, because the child has needs and activities, as parents do, and may not want to be pulled away from friends. This may call for adjustments you will make for your child. Some of them will come quite soon. Expect new abilities, new language, new understanding--and new willfulness, new rebellion, and maybe some tantrums.

It will be tempting to blame the divorce. Please don't. Divorce may make her behave worse than she would have (or even better), but the changes would occur anyway. A 2-year-old must become independent, and they do it by standing up for their rights--and for quite a few they don't have at all. It's part of growing up.

With all these givens, and all these ifs, joint custody is well worth trying. It's a good solution to a sad situation but not a perfect one. Nothing is. Such an arrangement does, however, recognize that both parents have the right to nurture their child. And it recognizes that the child has the right to grow up with the love and the wisdom (or even the lack of it) of both a mother and father, if it's at all possible.

Q: My problem is not unusual. I am a single parent of a 3 1/2-year-old son. His father and I separated when he was 9 months old, and he has not seen or heard from him since, which is his father's choice. We are now divorced.

I have a good job, and we have a nice home. I work 9 to 5, while my son is in a day-care center. His teachers tell me he is a very well-adjusted child and very bright. They said he is ready to move up to the 4-year-old group.

I have been dating a man now for a year. He gets along well with my son and helps him do things as a father would.

My son has asked me before where and who his father is, but still he seems confused about his father. He asks me when I will get married again so he will have a new father.

I have no plans to marry in the near future. How can I explain it to him so he can understand?

A: You can't. Even the brightest preschooler can't understand abstractions. You simply recognize that he is talking from his egocentric heart. He would like to have a man about the house--not for you, but for him. And so you treat his question like you would treat anything else that is your decision to make--by saying "not now" and "we'll see" and by tossing the ball to him. Ask him why he wants you to get married. You may be surprised to discover that he thinks a father in the house means dessert every night, since you serve it when your friend is there. Or that he'll go to Disneyland.

Sometimes a loaded question has a very simple answer.