DEAR ABBY: When I opened the newspaper today, in the front section was a photograph of Lucille Ball. Her blue eyes, red hair and lovely smile reminded me of my mother. My mother was only 49 when she passed away last month.

Mom had a hard life. She was weak from the beginning. She weighed 1 pound at birth and had only one lung. Her whole life, she hated going to doctors. I try to comfort my stepfather because he blamed himself for not forcing Mother to consult a doctor when she first started feeling sick.

Abby, please tell your readers that if they have a parent who is sick, and he or she says, "Don't worry about me, I'll be fine," TAKE CHARGE. Sick people don't always know what's good for them, especially when they're as stubborn as a red-headed woman. -- OLDEST DAUGHTER MISSING MOM

DEAR DAUGHTER: I offer my condolences for the loss of your beloved mother, who died at such an early age.

I'm pleased to pass along your important message. Sometimes serious symptoms can be "vague" -- as in heart problems in women. If they persist, the safest thing is to have them checked by a physician. There's truth to the saying, "An ounce of prevention is worth a pound of cure." In a case like this, an ounce of prevention can be lifesaving.

DEAR ABBY: I am facing a serious problem. I have an 18-month-old son. His father refuses to do anything for him -- with the exception of supporting him financially. He considers our child to be an 18-year debt -- not a son.

I'm 21 and can make it without his support. I want to terminate this man's rights to my son and stop the support payments. My little boy will never know this man as a loving father, and I want to remarry and have someone adopt him.

Everyone around me says I am stupid to want such a thing, that I should continue to make him pay. I want what is best emotionally for my son. Abby, what should I do? -- DESPERATE MOTHER IN N.C.

DEAR DESPERATE: Considering the lack of attachment the boy's father has for his child, I sympathize with what you would like to do. Consult a lawyer and discuss the advisability of terminating the legal arrangement you now have. That way, you will know if there are any financial pitfalls ahead.

DEAR ABBY: I am in the midst of planning my wedding and have been going over the guest list. I have a former brother-in-law I want to invite, but I've been told by several people that it's not proper to invite an "ex."

My former brother-in-law and I have always maintained a friendship, and I still feel close to him. He's like family. He and my sister ended their marriage on good terms, and they've stayed in contact because of their children.

Abby, what's the proper etiquette for inviting ex in-laws to a formal function? -- MINNEAPOLIS BRIDE-TO-BE

DEAR BRIDE-TO-BE: Since your former brother-in-law is on good terms with your sister and still "family" to you, there is no reason to exclude him from your wedding. By all means, follow your instincts and invite him. He deserves to be a part of your celebration.

To receive a collection of Abby's most memorable -- and most frequently requested -- poems and essays, send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby's "Keepers," P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: I am a 42-year-old woman who has been acting like a catty teen-age girl. My daughter "Erica" has been best friends with "Alexa" since preschool. Both girls are now in high school. Alexa has blossomed into a beautiful girl, while my Erica is a rather plain Jane. Alexa always has a boyfriend. Erica has never had one. When Alexa is around, Erica is invisible to boys. They call her only to ask about Alexa.

Alexa's boyfriend wanted to make her jealous, so he broke up with her and began flirting with Erica. I knew what was going on, but I allowed it to happen. Just once, I thought, maybe a boy will notice Erica and see how special she is. Maybe this time she will get the boy.

Well, his plan failed. He couldn't get Alexa back, so he began spreading vicious rumors about her. (You know, the kind of rumors boys like to spread about girls.) Since we had been close for so long, people came to me to ask if the rumors were true. By not denying them, I implied that the rumors were true. I helped him to tarnish her reputation.

I guess I thought if Alexa looked bad, Erica would look better. He soon tired of his game and moved on, leaving Erica without a boyfriend and also without a best friend. Alexa eventually moved on to new friends.

I am so ashamed of what I did. I would do anything to fix it. What should I do? -- ASHAMED IN PITTSBURGH

DEAR ASHAMED: There's an old saying, "The authenticity of a painting is like a lady's virtue. Once questioned, it is never quite the same again." Short of admitting what a terrible thing you did to an innocent young girl, there isn't much you can do to repair the damage you allowed to happen. By failing to help your daughter see that she is special in her own way, and that her chance for popularity will come when young men begin to appreciate qualities that are more than skin-deep, you let both girls down.

Alexa has gone on and made new friends who accept her for who she really is. I'm particularly sorry for Erica, who has lost her best friend. I advise you to schedule some sessions with your spiritual adviser for yourself, and a psychologist who can suggest some healthy ways to build your daughter's self-esteem.

DEAR ABBY: My husband and I have been married 10 years. We have a happy marriage except for one problem -- he insists on having his friend over every weekend. When I ask him if we can please have a weekend to ourselves, or if he can ask his friend to leave early (midnight instead of 3 a.m.), we end up in a fight.

Abby, this has been going on for several years. I love my husband very much, but I'm fed up with this situation. Am I wrong for wanting to spend a weekend alone with my husband and children? -- NOT HAPPY SHARING HUBBY

DEAR NOT HAPPY: This has been going on for years? You have been incredibly tolerant. Your husband either feels sorry for his friend, or he's getting something from him that you and the children are unable to give him. Either way, you and your children are being left out in the cold.

Professional marriage counseling for you is a must. If your husband won't go, go alone. It will help you find the root of this unusual situation.

For an excellent guide to becoming a better conversationalist and a more attractive person, order "How to Be Popular." Send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby Popularity Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)

DEAR ABBY: I agree with your advice to "Concerned Knoxville Mom," who would like to scare her latchkey daughter into not opening the door to strangers. However, I have a better solution.

Mom should take the girl for a frank chat with a police officer who can relate actual horror stories. Perhaps arrangements could also be made for a police officer to address a school assembly occasionally on the topic of personal safety. The police would much rather prevent crimes than solve them. -- ROGER LEONARD, BOWIE, MD.

DEAR ROGER: That's a terrific idea. I love it when readers help each other. I'm sorry I didn't think of it. Read on:

DEAR ABBY: This is in response to the mother who allows her 10-year-old daughter "Amber" to stay home alone after school. If that mother would walk in my shoes for just one day, she would immediately abandon the practice. I am an emergency department nurse who has seen horrors occur to 10-year-olds who were left unsupervised.

I have tried frantically to blow life back into a 10-year-old boy who plunged into the icy water of a pond after he attempted to walk across too-thin ice. I have held the hand of a 10-year-old girl during an exam after she was brutally gang-raped by neighborhood teen-agers. I have heard the screams of a 10-year-old boy whose body was 100 percent burned in a raging house fire. I don't think I need to go on.

I realize children have different levels of maturity, but we must never forget that they are indeed children. How difficult would it be for "Concerned Mother" to find a teen-ager who would be willing to earn a few dollars to be with Amber for a few hours after school?

Some states have laws that prohibit children under a certain age being left alone. In Pennsylvania, the age is 12. If Amber were here in Pennsylvania, the "concerned" Knoxville mother would be arrested.

Please print this so that some parent who may not have considered all the consequences of leaving a child alone may see it. If it saves just one child from injury, it will be worth it. -- MORE CONCERNED IN YORK, PA.

DEAR MORE CONCERNED: I like your idea of getting a teen-ager to stay until the mother returns from work. If she has not already done so, the mother should also look into organized after-school activities for children of working parents.

DEAR ABBY: After reading the letter from "Tired of the Roots in Pennsylvania," about her boyfriend's fetish for women with blond hair, I'd like to throw in my 2 cents:

Many years ago (I am now 86), I had a blind date with a supposedly nice man. We went to a concert in a park. While we were walking up a hill, he went a little haywire when he noticed a blond woman walking about 10 feet ahead of us. He speeded up, and in order to keep pace, so did I. As soon as we got ahead of her, he turned around to look at this "blond goddess" and found himself staring at a woman who was close to 90! It proved how true is the saying, "Don't judge a book by its cover."

If my poor blind date had been wearing false teeth, they surely would have fallen out! Needless to say, our first date was our last. -- GRAY-HAIRED GRANNY, LAGUNA HILLS, CALIF.

DEAR GRAY-HAIRED GRANNY: Perhaps the saying should be modified to: Don't judge a book by its front -- or back -- cover. The lesson your date learned holds true today: Flowing tresses do not necessarily mean a lovely young maiden is beneath them.

What teens need to know about sex, drugs, AIDS, and getting along with peers and parents is in "What Every Teen Should Know." To order, send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Teen Booklet, P.O. Box 447, Mount Morris, IL 61054-0447. (Postage is included.)