DEAR READERS: Over the past three weeks, I have devoted each Wednesday's column entirely to the intelligent and heartfelt responses I've received since I asked readers to tell me how they just said "no" to sex. Today's is the last in this series.

DEAR ABBY: How should a girl diplomatically say "no"? She can say, "Take me home and we'll see if it's OK with my parents." Or, "Let's wait until I get my blood test back." Both suggestions should cool the young man's ardor.

But if the situation has progressed so far that sex is the next step, the girl has already gone far beyond the point where she should have said no, and there's no longer a way to be diplomatic or pleasant. I offer some suggestions on what to say then, and the young lady should speak loud and clear: "Take me home. What's the matter with you? My daddy will make you a soprano!" "When were you last checked for a sexually transmitted disease?" "Did you know my father likes to come out here and see who's making out?"

I hope these suggestions prove helpful. Hang in there, Abby. You make the world a better place. I'm an avid fan, but please don't print my name. I'm ... A (MALE) DENTIST IN MISSOURI

DEAR ABBY: I'm 24 years old. I've been pregnant and have also had an STD. I know firsthand how difficult it is to say "no." It's not a matter of being rude. It's a fear of not being liked if you don't have sex, not being aggressive enough to refuse, and wanting someone to make you feel "loved." Abby, it's scary to say no, especially if you have low self-esteem. But I've finally learned to do it.

Sometimes I still feel self-conscious -- and scared, too. But that's natural. What's not natural is being 16 or 17 or 18 and being alone and pregnant or having AIDS.

It's OK to be rude if you have to be, and it's also OK to say "no." If you feel like you can't say "no, that's when you have to muster up your self-confidence and say, "Who cares if this person doesn't like me? I like myself and care enough about myself enough to refuse!" -- SAY YES TO YOURSELF IN MINNESOTA

DEAR ABBY: I'm 24 years old. I've been pregnant and have also had an STD. I know firsthand how difficult it is to say "no." It's not a matter of being rude. It's a fear of not being liked if you don't have sex, not being aggressive enough to refuse, and wanting someone to make you feel "loved." Abby, it's scary to say no, especially if you have low self-esteem. But I've finally learned to do it.

Sometimes I still feel self-conscious -- and scared, too. But that's natural. What's not natural is being 16 or 17 or 18 and being alone and pregnant or having AIDS.

It's OK to be rude if you have to be, and it's also OK to say "no." If you feel like you can't say "no, that's when you have to muster up your self-confidence and say, "Who cares if this person doesn't like me? I like myself and care enough about myself enough to refuse!" -- SAY YES TO YOURSELF IN MINNESOTA

DEAR ABBY: My advice to women and girls who want to avoid unwanted sexual encounters: Tell them up front that you're not ready for sex. Avoid sexual situations. Stay out of bedrooms, back seats and dark corners. Use your head and stick with the group. Don't use alcohol or drugs, or the drug will be making the decision -- not you. Be as rude as you have to be and don't worry about it! Your long-range plans for yourself are important -- and they'll be better served if you are tagged "rude" rather than "easy."

Listen to me: I made every mistake in the book, and my children and I paid a terrible price for it. You young women are our future. You are beautiful. You are important. Your lives are worthwhile. Take care of your lives and the children you will someday have. Please! -- LEARNED THE HARD WAY.

DEAR READERS: Thank you for your eloquent and caring letters. I was touched by how many of you wrote to share your experiences in the hope that they might help someone else. I regret that space limitations prevent me from printing them all.

For everything you need to know about wedding planning, order "How to Have a Lovely Wedding." Send a business-sized, self-addressed envelope, plus check or money order for $3.95 ($4.50 in Canada) to: Dear Abby, Wedding Booklet, P.O. Box 447, Mount Morris, Ill. 61054-0447. (Postage is included.)

DEAR ABBY: I am a 66-year-old married man. My wife and I were childhood sweethearts and have been married for 46 years.

Six years ago, she developed Alzheimer's disease and has been in a nursing home for the last year.

Even though she does not recognize me or our children, I have gone to visit her every day, until six months ago when I reduced it to twice a week because she had no idea who I was, which I found very depressing.

The nursing staff and my children noticed my depression and encouraged me to "break away." As I reduced my visits, I wound up with a guilty conscience that is difficult to cope with.

My children have encouraged me to seek female companionship, something I had longed for, but I was concerned about what others would think.

However, for the last four months I have been romantically involved with a 62-year-old neighbor lady whose husband died nine years ago. We have taken a few trips together. My children and brothers and sisters enthusiastically approve of our relationship and say they have noticed a positive change in me.

Abby, my guilt feelings have increased even though I haven't changed my visiting routine to the nursing home. I would greatly appreciate your comments on my situation. -- TORN IN OLYMPIA, WASH.

DEAR TORN: I can understand your feelings of guilt. Fate has placed you between a rock and a hard place. You are a married man with an absentee wife.

A psychiatrist, psychologist, grief counselor or clergyperson could help you absolve those feelings.

If there is an Alzheimer's support group in your area, join it. There are thousands of support groups for caregivers of Alzheimer's patients, and the national office of the Alzheimer's Association (1-800-272-3900) will be happy to refer you.

Incidentally, on Oct. 5 and 6 in more than 200 communities, the Alzheimer's Association will hold its 1996 Memory Walk, the only nationwide event for Alzheimer's disease, to raise funds for caregiver programs.

DEAR ABBY: I am 36 years old and my husband is 38. We have been married three years. This is a second marriage for both of us, and I consider myself the luckiest woman in the world.

I have never had children but my husband has one -- a 10-year-old son who is living with his mother in another state.

Abby, I am tired of being asked, "When are you two going to have a family?"

I honestly do not want children and my husband doesn't want children -- in fact he had a vasectomy shortly after his son was born.

What do you tell people who keep asking, "When are you two going to have a family?" -- SICK OF IT

DEAR SICK OF IT: Use the "Dear Abby" response when you are asked a question you don't want to answer:

"If you'll forgive me for not answering, I'll forgive you for asking."

DEAR ABBY: My father-in-law is basically a nice person, but after 20 years, he has yet to recognize me as a person. I am simply "Ken's wife."

I have been a very conscientious daughter-in-law, remembering all the special occasions, Father's Day, his birthday, etc. But despite my efforts he still treats me like I am invisible.

Each Christmas, he presents my husband with a nice check (in front of me). It is in an envelope bearing Ken's name. I try to ignore the slight, but each time I feel that I have been slapped in the face.

Abby, am I being petty? Or do I have a point? -- SENSITIVE CANADIAN

DEAR CANADIAN: You are not being "petty" and you do have a point. Your father-in-law is incredibly insensitive. Your husband should "educate" him in the social graces. He should remind his Dad that you have a name.

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, Ill. 61054-0447. (Postage is included.)

DEAR ABBY: I am asking you to please help us alert all Americans about the danger of children becoming involved with drugs. The best preventative is for parents to take the time to consistently talk to their children about drugs, alcohol and tobacco from the time they are old enough to understand. I can think of no better way to get this important message before the public than your column, and that's why I hope you'll print my letter to parents. -- GEN. BARRY MC CAFFREY (RET.), DIRECTOR, OFFICE OF NATIONAL DRUG CONTROL POLICY

DEAR GEN. MC CAFFREY: It is a pleasure to help spread the word. Your vital message is one that all parents should take to heart:

DEAR PARENTS: As your children begin this new school year, take the time to talk to them about the dangers posed by illegal drugs, alcohol and tobacco.

Some questions and answers to get you started discussing these topics with your children:

-- Why should you avoid illegal drugs like cocaine, heroin, marijuana, methamphetamine and LSD? Because your central nervous system is still developing. If you use these drugs, you risk impairing that development and causing permanent brain damage.

Psychoactive drugs affect your brain and impair judgment. Under their influence, you are more likely to endanger your life or a friend's. You will be less able to protect yourself from physical or sexual assault.

These drugs are addictive. You are not in control of how they affect you. You could become dependent on them very quickly. Smoking marijuana is illegal and a possible gateway to more dangerous drugs. A 12-year-old who smokes marijuana is 79 times as likely to have an addictive problem later in life as a non-marijuana-using child.

-- Why should you avoid alcohol (including beer, wine, wine coolers and mixed drinks)? Because alcohol is the second leading cause of preventable death in our nation, claiming more than 100,000 lives a year.

Adolescents are twice as likely to be involved in a fatal, alcohol-related crash as adults.

Half of sexual assault and date-rape cases involve alcohol.

Alcohol-related driving accidents, violence and suicide are the three greatest causes of death among American youth.

Drinking is illegal if you are under 21.

-- Why shouldn't you smoke cigarettes? Because nicotine is the leading cause of preventable death in our nation, claiming more than 400,000 lives a year.

Each day another 3,000 kids will begin smoking. One-third of them will probably have their lives shortened as a result.

Children who smoke cigarettes are 5.9 times more likely to use other illegal drugs. A 1994 study by Columbia University's Center for Alcohol and Substance Abuse found that 83 percent of those who used cocaine identified smoking cigarettes as a gateway behavior.

It is important to speak CONSISTENTLY to your children about these dangerous drugs throughout the year, not just at the beginning of the school year. About one in 10 of our children aged 12 to 17 are now using illegal drugs. They do not understand the associated risks. You can help your children appreciate what's at stake if they smoke cigarettes, drink alcohol or use illegal drugs. If you don't, your child is more likely to risk his or her mental and physical health.

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, Ill. 61054-0447. (Postage is included.)