All barrier methods are used around the time of intercourse to prevent sperm from entering the uterus. There are a number of female options, but only one male option.

CONDOMS

Modern sexual education efforts have focused on condom use to prevent unwanted pregnancies and reduce the spread of sexually transmitted infections. It fits over top of the penis and collects sperm in the tip, thereby preventing it from entering the vaginal canal. 

Condoms aren’t perfect. Typical use leads to a pregnancy rate of 13% per year. Not great odds. They fail because they’re not applied correctly, they fall off during intercourse, they burst open, or they’re simply not used every time.

Advantage: they’re the only method of birth control that can prevent the transmission of infections. This is typically not an issue with married couples, but it’s a big issue for those couples not in exclusive relationships.

Advantage: cheap, readily available, easy to use.

Advantage: doesn’t affect fertility when a couple wants to try to get pregnant.

Advantage: no medication to take and no side effects, unless someone’s allergic to latex.

Disadvantage: sometimes couples “forget” to use them. In the heat of the moment, correctly applying a condom may not be a high priority. 

Simply put, condoms work reasonably well in the short term while using another method of birth control, but long term they’re a hassle.

SPERMICIDE

The active ingredient in spermicide destroys sperm, leaving them immobile and unable to bind to an egg. It can be used alone by applying it high into the vaginal canal at least 10 minutes before intercourse. It comes as a gel, cream, foam, or embedded within a sponge. Failure rate when used alone is about 20%. Spermicide commonly causes mild skin irritation to both partners. 

FEMALE BARRIER METHODS

The diaphragm is a silicone dome that fits inside the vaginal canal. It’s a one-size-fits-all device that is generally soft enough to be comfortable when properly inserted. A cervical cap does the same thing, but is smaller, stiffer, and comes in a variety of sizes. Both diaphragms and cervical caps are reusable for a year or more, which means they must be washed and properly stored.

All female barrier methods are designed to work with spermicide. The spermicide jelly is applied to the device before insertion, then left in for six hours after intercourse. Spermicide modestly increases their effectiveness.

As with male condoms, female barrier methods have a high failure rate, up to 20%. They require motivation to use at every encounter and take some skill to apply correctly.

Overall, female barrier methods are not a common means of birth control. They’re messy and a hassle to apply every time. Combine that with their high failure rate and it’s no wonder they’re unpopular.