If you or your lover have just had four other sexual partners in your lifetime, you will almost definitely be one of those infected. So even if you think it's impossible that the person you are getting naked with has an STD, the stats aren't exactly in your favor.

Nor will condoms always keep you safe. Though they're still essential for preventing STDs like HIV and gonorrhea, they won't necessarily protect you from genital herpes or warts.

Maybe you need a wake-up call: There are more than 20 kinds of STDs and they are transmitted in different ways.

Kissing Risk

While sexual intercourse is the highest risk activity for all types of STDs, herpes and hepatitis, for example, can be passed through kissing.That is why no form of getting to know someone physically is entirely risk free -- from smooching to foreplay to oral, anal or vaginal intercourse.

During Sexual Health Week (August 1-7), the Family Planning Association wants more people to take care of their sexual health.

Protection has never been more important. In Scotland, cases of chlamydia rose by 88 percent between 2000 and 2003, while HIV infection from heterosexual sex has more than doubled in the UK between 1999 and 2003.

Here, Cosmopolitan magazine gives advice and tips on how to be "Happy, Healthy & Sexy" from their book on women's sexual health:

Five Healthy STD Prevention Habits

1. Get tested. If you have any STD risk at all, make sure you include a screening in your annual gynecological check-up.

2. Remember, you're not just having sex with that person, but with everyone they've slept with -- and everyone they've slept with.

3. Don't rely on finding symptoms. Many of the most common STDs -- especially HPV, chlamydia and herpes -- produce no obvious symptoms in up to 75 percent of those infected.

You're much more likely to notice if you've contracted trichomoniasis, thrush or bacterial vaginosis (which causes an unusual discharge), gonorrhea (which makes it painful to urinate), or syphilis (which is signaled by a tell-tale sore).

4. Don't have sex with someone new when drunk. You are less likely to use a condom or use one correctly.

5. Know when to use what.

Could You Have an STD and Not Know It?

Some symptoms of STDs are eerily like those of other kinds of infections.

They may not even show up in the genital area. Here is your "See Your Doctor Now" checklist:

See Page 2 for Quiz: Are You STD Savvy?