The Catholic Church has been a major opponent of the birth control movement. While the Catholic Church accepts abstinence from intercourse and use of the so-called rhythm method (limiting intercourse to the least fertile periods in a woman's monthly cycle) as acceptable birth control activities, it strongly and vocally opposes other methods.

For individuals who choose to use birth control, various approaches are available. Considerations in selection include safety (e.g., protection from sexually transmitted diseases and HIV, as well as avoiding side effects of birth control use), effectiveness, convenience, cost, personal acceptance, and partner attitudes. All methods of birth control have their advantages and disadvantages. The oral contraceptive pill (often called "the pill") has become a widely used medically prescribed birth control method in many parts of the world. The pill consists of two synthetic hormones that are equivalent to estrogen and progestin, pituitary hormones that regulate a woman's menstrual cycle. Most forms of the pill block a woman's ovaries from releasing eggs. Used appropriately and consistently for 21 days during the monthly cycle, the pill has been found to be 97-99% effective in preventing pregnancy. This high level of success, as well as the fact that the pill is easy to use and does not disrupt intercourse, has made it particularly appealing. For younger women, the pill also may reduce the risk of various diseases including cancer of the ovaries and endometrium, benign breast cysts, premenstrual syndrome, and iron-deficiency anemia. However, the pill confers no protection from sexually transmitted diseases (STDs) or HIV; also, its use may promote nausea, weight gain, and increased blood-clotting. Taking the pill also has been found to be associated with heightened risk for cervical cancer. Women who take the pill are expected to have regular gynecological exams and to report any symptoms (e.g., unexplained vaginal bleeding, abdominal pain, dizziness, depression) to their primary care provider. Certain women (e.g., those over the age of 35, heavy smokers, those with various heart or vascular problems, those with a history of cancer) are discouraged from taking the pill.

The diaphragm is a bowl-shaped flexible cup that is inserted into the vagina so that it covers the cervix. Commonly used with a spermicidal cream or jelly that kills sperm, the diaphragm stops sperm from entering the uterus. Spermicidal use is important with diaphragms because they are not completely effective in stopping sperm. When used carefully, diaphragms have been found to be 82-95 percent effective in preventing pregnancy and they may provide some protection from STDs. Diaphragms must be fitted by a physician to insure that the right size is being used. They can be inserted into the vagina up to six hours prior to intercourse and may be left in place for 24 hours after intercourse (and must be left in place for at least six hours to insure effectiveness). If intercourse is repeated during this period, additional spermicide can be inserted without removing the diaphragm. Annual gynecological check ups and diaphragm checks are recommended, especially if the woman's weight changes or she recently has had a pregnancy. Potential side effects include irritation, bladder infection, and unusual vaginal discharge. The most significant potential health risk of using the diaphragm is toxic shock syndrome. Symptoms, which should be reported to one's primary care provider immediately, include vomiting, high fever, diarrhea, a sunburn-like rash, and general itching in the genital area.

The condom is the most widely used male contraceptive. It is made from thin rubber, polyurethane, or animal tissue and covers the penis, blocking sperm from entering the vagina. Condoms are now widely and easily available in most parts of the U.S., in pharmacies and AIDS prevention projects, and are available in varying colors, with and without lubricants, and with and without spermicide. Sometimes they are used with foam or vaginal inserts which contain a chemical that stops sperm from swimming. Used correctly, condoms by themselves are 88-92 percent effective in preventing pregnancy. Foam used alone is 72-97 percent effective in pregnancy prevention. When used together, condoms and foam or vaginal inserts are 98-99 percent effective. Latex and polyurethane (but not "natural" animal skin) condoms are also effective in preventing the transmission of STDs and HIV. Moreover, these methods are relatively inexpensive, are available without a prescription or doctor's exam, and have few if any side effects (although some people have allergies to spermicide or latex). Condom failure is often the consequence of improper use, especially failing to leave a small space at the head of the condom to catch the ejaculated semen, or having the condom come off while the penis is still in the vagina. Care must be taken as well to use a finger to hold the condom in place when removing the penis from the vagina to avoid spillage. On the negative side, condoms must be replaced before each time intercourse occurs and many men complain that condoms dull physical pleasure. Recently, a female condom has come on the market, although it is still comparatively expensive. The female condom consists of a loose-fitting, lubricated polyurethane sheath (that is inserted into the vagina) and two flexible polyurethane rings. One ring is fixed at the closed, narrow end of the sheath and serves as an insertion device, the other ring forms the opposite external edge of the sheath and remains outside of the vagina covering the external labia. Because the female condom is relatively new, many women have not had experience with it and its popularity is not yet determined.

A range of additional contraceptives are readily available, including the cervical cap, a thimble shaped rubber or plastic cap that fits securely over the cervix and extends into the vagina. Used with a spermicide, the effectiveness of the cap is comparable to that of a diaphragm. Like the diaphragm, it can be inserted long before intercourse (but can be left in for up to 3 days after intercourse) and is found to be more comfortable than a diaphragm by some women.

Depo Provera is a long-lasting birth control method that involves injection of a synthetic hormone called progestin every three months. The drug has been found to be almost 100 percent effective in preventing pregnancy, but is associated with a long list of possible side effects including headaches, weight gain, irregular bleeding, depression, nervousness, dark spotting of the skin, change in hair growth, and change in sex drive.

The Intra-Uterine Device (IUD) is a plastic object, often t-shaped, that is medically inserted into a woman's uterus. The IUD contains copper or a hormone that prevents sperm from joining with the egg. Found to be 97-99 percent effective in preventing pregnancy, IUDs may cause tubal pregnancy, menstrual cramping, and infection.

Norplant is a long-term birth control method that involves the medical insertion of six soft capsules (about the size of a match stick) under the skin of the upper arm. The implant releases the synthetic hormone progestin into the body over a five-year period preventing the ovaries from releasing eggs. This method is over 99 percent effective but is associated with a range of side effects including irregular menstruation, weight gain, change in appetite, acne, headaches, gain or loss of facial hair, depression, nervousness, and ovarian cysts.

Finally, there are surgical procedures: vasectomy (to block the vas deferens tubes that carry sperm) in men and tubal ligation (blocking the fallopian tubes that transport eggs) in women. These are extremely effective birth control methods. Like all surgery, there are some risks, but they are rare in both procedures. Tubal ligation is relatively expensive (over $1000); vasectomy is somewhat less expensive. Both of these procedures are surgically reversible (an expensive procedure) with relatively high success rates. Neither of these methods, however, prevents the spread of STDs or HIV.