STI's

[gucci]

How can a female and a male who have not had intercourse before not catch STI's or STD's (this is what I have been told through sex education at school) whereas someone who has had sex whether it be unprotected or protected sex have STI's or STD's? I have been wondering this for a little while now.

[Oblivion]

It is impossible for an STD/I to be transferred unless one person or the other has it. The only way you can get it without having sex is from birth.
You get STD/Is from unprotected sex because some diseases, such as AIDS, are transferred by blood or reproductive fluids, such as semen. You can also get skin contact/bodily fluid diseases, like oral/genital herpes.
You can get STD/Is from protected sex if one partner or the other has a skin contact disease.

Sexually transmitted diseases and infections don't just appear when you have sex; one person has to have gotten it from a parent at birth, or from another person during sex to get it. Condoms reduce the chance of all STD/Is, although there is still a risk, if the condom breaks, slips, etc. or with skin contact diseases, they don't always cover the infected skin.

[Mzor203]

Pubic lice/crabs is an exception, they can be obtained by sharing covers with someone who has them, if they're not washed well. Logically you could get them other ways, because they are alive and can travel. But otherwise, what Nick has stated is correct.

Oh and just remembered, sharing needles with other people who have STD's can transfer them. That is one of the main reasons AIDS is spreading so fast, needle sharing. So basically, don't do drugs and you'll be fine.