Glossary

Pregnancy that happens outside the uterus, such as pregnancy occurring in the fallopian tube.

An egg is the sex cell of the woman. It must meet with sperm to cause a pregnancy. Usually one egg comes out of the woman's ovary about two weeks before every period. When it leaves the ovary, it goes into of the fallopian tubes. When a woman has intercourse, sperm swim through the tube to meet with an egg.

When semen leaves a male's penis during an orgasm. Usually only a teaspoon or tablespoon comes out at a time. About 500 million sperm come out with the semen. This can happen when he has sex, when he masturbates or even when he is asleep (wet dream). If a male doesn't ejaculate during sexual contact, he will not be harmed. A male can ejaculate with or without having an orgasm. It is not the same as urinating (peeing). Urinating and ejaculation cannot happen at the same time.

When a pre-embryo (zygote) grows and gets to be a certain size and sticks itself to the inside of the uterus it becomes an embryo. It takes eight weeks after fertilization for the embryo to grow into a fetus.

Swelling of the brain that may be caused by germs or viruses that cause herpes, syphilis, or gonorrhea.

When a penis gets stiff and hard. This happens because blood flows into it. This might happen because someone is sexually excited, but it can also happen at other times.

Being exposed to a STD means that you were in a situation in which you had a chance to "catch" it. You can be exposed to a STD by having sex with an infected person. You can lower your chance of being exposed to a STD by not having sex or by using an effective barrier method, such as a condom.