I am a 17-year-old girl, and I guess that a lot of my friends are no longer virgins. So far, I have clung to my virginity, despite the efforts of several boys who have tried real hard to persuade me to give in. I am at college, and I want to do well in life and make a good career for myself, so maybe it is best if I don't have sex for a while.

On the other hand, my two best friends tell me that sex is wonderful, and that I don't know what I am missing. One of them says that when she goes to bed with her boyfriend, it is like being in paradise!

Is she exaggerating, Doc? Am I really missing out on a lot of intense pleasure and fun? Or am I safer if I preserve my virginity for a little longer?

I guess I have to make up my mind soon, because already I have let a couple of guys touch me down there. I liked it. And I am aware of the fact that it wouldn't take much now for me to go all the way.

A Well, yours is a really sensible and thoughtful email, and I know it will strike a chord with a lot of young women. As you are discovering, there are two factors which propel a girl towards losing her virginity:

First, the sex urge is enormously powerful, and in many young people there is an almost irresistible urge to have intercourse;

Second, there is a lot of pressure from friends who keep telling you that you are missing out on enormous pleasure and fun.

However, it IS possible to resist the urge to have sex. There are plenty of young people who keep saying 'no' - and who remain virgins till well into their 20s.

Also, it IS possible to resist peer pressure. Please bear in mind that some of your girlfriends who talk about how wonderful sex is are only doing it to seem mature and to impress other folks! Very often, teenagers who talk about how great sex is have NOT actually had it ...

You ask whether your friends are exaggerating about the pleasure they have had from sexual intercourse. The answer is, probably they are. Many surveys have shown that a high proportion of girls are real disappointed with their early experiences of sex. Often, it all turns out to be a lot messier and more painful than they thought. And again and again, they report that 'it was all over so quickly!' That is because many young men are not too good at controlling themselves - and discharge almost immediately.

Indeed, for many females, sex does not become a great pleasure until they have spent quite a long time in learning how to enjoy it and how to discharge. Often, it is not much fun until they find a skilled and romantic guy who really knows what he is doing.

Now before you make up your mind about whether to lose your virginity, I would like you to consider the downsides of becoming sexually active. You would expose yourself to the following dangers:

You could easily get pregnant. That might perhaps mean the end for your chances of a good career.

You are quite likely to pick up a sexually transmitted infection. While some of these sex infections are easily treated, others are NOT, and they can blight your health for life.

You would probably soon pick up HPV - the virus which eventually causes cancer of the cervix.

Lastly, you ask me to tell you what is the best age to start having sex. There can be no precise answer to this question. For some girls, sex at 17 works out fine. For others, putting it off till 21 or 22 is a lot wiser. The choice is up to you.

A No. It is just one of many misconceptions that surround masturbation. Pay it no mind.

A At your age, this kind of severe insomnia is nearly always caused from depression. Please see a doc in the next few days, to talk things over and get some treatment. I wish you well.

A Forgive me for shortening your very long email, but it is obvious that you are being reinfected by your partner.

You see, guys often carry minor sex infections without realising it, because very often they do not get any symptoms!

So what is happening is that every time you get treated, your boyfriend then gives you more germs. The answer in these cases is simple: Next time you get treated, HE must get treatment too.

A Unfortunately, stretch marks on the belly are an extremely common result of the abdominal skin being distended during pregnancy.

I am afraid that doctors do not have any cure for stretch marks - though if they are real bad, it is sometimes possible to take plastic surgery. The cosmetic industry produces various creams and potions which are supposed to be good for stretch marks, but I do not think that there is any scientific evidence that they work. Sorry.

One final point: Avoid getting overweight - because that will probably make the marks look worse.