It is impossible to write about teenage sex and ignore the health risks. A teenager today is three times more likely to contract a sexually-transmitted infection (STI) than to be a party to a pregnancy.

When I read Kathryn Holmquist's article "Virgin Promotions 2001" last May, I was stunned at her suggestion that my book Sex and Young People implies that "sex is dirty, dangerous and sinful", and her allegation that I set out to put fear into young people.

The opposite is true.

I describe sex as a positive, exciting and fulfilling experience and condemn the unhealthy religious teaching of the past that stimulated sexual guilt.

I stress the importance of open and honest communication.

In my book, I wrote: "Until you feel you can resist sexual pressure and feel confident that you can recognise manipulation and sexual deception, your decision about when to have sex will not be freely made." Sexually-active teenagers need to learn that condoms fail and there are risks even from having protected sex.

It is not my intention to frighten young people. If it were, I could have written about comforting a 14-year-old girl who was told by her doctor that she could never have a natural childbirth because she had experienced several severe outbreaks of genital herpes.

Subsequently, I discovered that the information her doctor gave her was not fully accurate. Women with herpes can get treatment and don't always have to have a Caesarean section when they give birth.

A distraught 17-year-old girl confided in me that she had HPV, genital warts - in her throat. She begged me to talk to students about the need for protection when having oral sex.

I discussed the chapter on sexually-transmitted diseases with three college students - two young men and a young woman. One of the men had never heard of genital warts.

He told us he had fleshy growths on his penis that he didn't like but had no idea that it could be a sexual infection.

One of the others was able to tell the boy how to go about having it checked out because he himself attended an STD clinic. I could go on and on.

A GP in a small town made a point of talking to me before I went to work with fifth-year students.

She said: "It's probably unethical for me to be doing this. I have three girl patients from that school who have contracted genital herpes from the same guy. Will you please warn the students that there are risks, even when they have protected sex."

Stories like this instil fear in me. I am terrified that young people are having sex too soon and that they are ignorant of the risks. All it takes is one unfortunate experience with the wrong partner and a teenager could end up with a virally-transmitted sexual disease for life.

Sexual diseases are frightening and they do dreadful emotional damage to the self-esteem of the young people who contract them. Condoms offer protection to the part that is covered, but, for virally-transmitted diseases, this leaves the pelvic and uncovered genital areas at risk.

Ms Holmquist recognises that what feels right in the heat of the moment may be regretted years later. She is correct. She asks: "Are young women who have lustful feelings and have a realistic understanding that a long-term commitment may not be a runner with a particular boyfriend supposed to feel like sluts?"

The double standards in our society are such that lusty lasses are labelled "sluts" by guys who are happy to applaud behaviour in men that is condemned in women.

I am shocked that a responsible journalist like Kathryn Holmquist can write that "sexually transmitted diseases are dangerous and rampant among teenagers and that condoms are not foolproof" and, in the same paragraph, advise that "it's important to choose partners carefully".

How on earth can young people do that?

In the book, I use the "relationship tree exercise" to explain that when a person is genitally intimate with someone else, they are also intimate with everyone who has been intimate with any person who was ever with that person. On a first encounter, that could be a connection to 20 or 30 people.

Many STDs have no signs or symptoms. People who are infected may look perfectly healthy and be unaware that they have a sexual infection.

The health promotion unit leaflet on sexually transmitted infections (STIs) stresses that anyone can be infected from a single sexual contact with an infected person. Anybody who is sexually active and not in a "one faithful partner relationship" is at risk.

How can you get that information across without sounding scary?

Labelling me a "self-appointed moral guardian" calls my professional competence into question. In my book Sex and Young People I make no attempt to impose any beliefs on readers. I give the information that empowers them to make healthy choices about their intimate relationships.

This is where I concur with Ms Holmquist, because my hope is that knowledge will encourage young people only to have intimate relationships with people who really care about them.

Carmel Wynne teaches RSE