Abstaining means not to have sexual intercourse.

Advantages:

• 100% effective (see below)
• Free
• 100% protection from sexually transmitted diseases (see below)
• No prescription or doctor visit necessary

Disadvantages:

• Sometimes difficult to resist peer pressure
• Sometimes difficult to resist boyfriend pressure
• Sometimes difficult to resist your own sexual urges

Limitations (almost nothing is 100%!):

Birth control: It is possible to get pregnant without having sexual intercourse. It has been reported many times in the medical literature and I have seen several cases myself. The situation in which it has occurred involved couples that engaged in heavy petting including ejaculation by the male in the area of the women's vagina. Some of the sperm swam into the vagina, back to the cervix, up into the womb and out the tube where one found the egg. A very unlikely occurrence, but there may be as many as one billion sperm in an ejaculation, and it only takes one.

Sexually transmitted diseases: Even without intercourse you can get sexually transmitted diseases. The most common one would be getting herpes from oral sex with someone with a fever blister or cold sore. It would also be possible to get genital warts from being touched by someone with warts on his hand. Other STD are possible but unlikely.