Condoms are considered a barrier method of contraception. There are male condoms and female condoms. A male condom is a thin latex (a type of rubber) sheath that is worn on the penis. A female condom is a polyurethane sheath with a flexible ring at either end. One end is closed and is inserted into the vagina, the other end is open and the ring sits outside the opening of the vagina. The male condom is far more widely used and is sometimes called a "rubber" or "prophylactic."

How Does It Work?

The condom works by keeping semen (the fluid that contains sperm) from entering the vagina. The male condom is placed on a guy's penis when it becomes erect. It is unrolled all the way to the base of the penis while holding the tip of the condom to leave some extra rubber. This creates a space for semen after ejaculation and makes it less likely that the condom will break.

After the guy ejaculates, he should hold the condom at the base of the penis as he pulls out of the vagina. He must do this while the penis is still erect to prevent the condom from slipping off when he gets soft. If this happens, sperm could enter the vagina.

The female condom is inserted into the vagina using the closed-end ring. The other ring creates the open end of the condom. The sheath then lines the walls of the vagina creating a barrier between the sperm and the cervix. The male and female condoms should not be used at the same time because they can get stuck together and cause one or the other to slip during intercourse, making them ineffective. The female condom can be inserted up to 8 hours prior to intercourse. It should be removed immediately after sex.

A used condom should be thrown in the garbage, not down the toilet. Once a condom is used, it cannot be reused. A new condom should be used each time you have sex and it must be used from start to finish every time you have sex to prevent pregnancy and sexually transmitted diseases (STDs). Never use oil-based lubricants such as mineral oil, petroleum jelly, or baby oil with condoms because these substances can break down the rubber.

And if a condom ever seems dry, sticky, or stiff when it comes out of the package, or if it is past its expiration date, throw it away and use a new one. It's a good idea to have several condoms on hand in case there is a problem with one. It's best to store unused condoms in a cool, dry place.

How Well Does It Work?

Over the course of 1 year, 15 out of 100 typical couples who rely on male condoms alone to prevent pregnancy will have an accidental pregnancy. The use of the female condom is a little less reliable and 21 out of 100 couples will have an unintended pregnancy.

Of course, these are average figures and the chance of getting pregnant depends on whether you use this method correctly and every time you have sex. In fact studies show that, although it's possible for condoms to break or slip during intercourse, the most common reason that condoms "fail" is that the couple fails to use one at all.

Experts used to think that using spermicide with a condom would decrease the pregnancy rate as well as help fight against STDs. However, more recent information indicates that this is not necessarily true and spermicide does not help make condoms more effective.