Condoms are a form of barrier contraception that also prevents the spread of certain STDs. Most condoms are latex consisting of a reservoir tip and base ring that is connected by a thin latex tube. There are a top side and a downside to each condom. When the condom bag is opened, the side where the reservoir tip is pointing up, unimpeded, is the top. To apply, the tip of the reservoir is pinched between two fingers, while the ring is then rolled over the erect penis. To remove grasp the base ring and pull the condom off before erection is lost. Wrap the used condom in a tissue, or tie it off, and dispose of the used condom. Female condoms consist of two rings, one with a closed-end, connected by a tube of latex to the opposite open, larger ring. The index finger is placed in the closed end, which is inserted into the vagina pushing the closed end in as far as possible. This discussion will solely focus on male condoms.[1][2][3]

The idea of placing material over the penis for barrier contraception has existed since the 15th century in Asia, where oiled silk paper or lamb intestine coverings were secured over the penis glans. In the 16th century in Italy, soaked linen tied onto the glans with ribbon was recorded as being used to prevent syphilis. The first use of the word “condom” was recorded in the 17th century when the English birth rate commission attributed a decrease in the English birth rate to these “condoms.” Rubber condoms were invented in the 19th century with latex condoms following shortly after in the early 20th century. Latex has since been the material of choice for condom manufacturers due to its thin mobility, ease of production, and non-porous nature making it an ideal barrier for semen introduction and STD prevention.[4][5]

Condoms function as barrier contraception preventing contact between semen and the opposite genitalia. It also prevents direct skin to skin contact of the penile glans and penis shaft and prevents contact from penile, vaginal, or anal secretions. Male condoms come in many different types, sizes, materials, colors, textures, odors, and flavors. Some include reservoir tips, special lubricants, or spermicides. Condoms come in various sizes from snug to medium to large.

Reservoir tips are designed to allow for ejaculate pooling. Condoms without reservoir tips may carry the risk of semen leaking around the sides to the back of the condom.

The vast majority of condoms consist of rubber latex (80%). Other materials used are synthetic (mostly polyurethane) (15%), and natural membrane (mostly lamb intestinal cecum, 5%).

Condoms can come in a variety of textures such as ribbed, studded, located on in the inside, outside or both sides of the condom. Condoms can also come bulb-shaped. These different textures and shapes are proposed to try and provide extra sensation to either the male or female partner.

Although rare, the risk of condom slippage or breakage during sexual intercourse has been reported in roughly 2% of cases. Latex condoms should only be used with water-based lubricants such as K-Y, saliva, and glycerin. Oil-based lubricants (e.g., baby oil, hand and body lotions, massage oil, mineral oil, edible oils, whipped cream) have been shown to interrupt the integrity of latex condoms and should not come in contact with latex condoms.[6][7][8]

Latex condoms most commonly last up to 5 years. Expiration dates are required to be placed on the outside of every individual condom pouch. When mixed with other solutions such as spermicide, the condom will have a much shorter shelf life (up to 2 years), due to the breakdown of latex.

For those with a latex allergy, synthetic condoms (polyurethane) and natural membrane (lambskin) condoms are an option. Synthetic condoms can function properly with both oil-based and water-based lubricants. Although natural membrane condoms can be used with both types of lubricants as well, they are porous and may be less effective at preventing viral STDs such as HIV, Hepatitis B, and herpes simplex virus. 

Some condoms come with the option of being coated in spermicide, most often nonoxynol-9 (N-9). Spermicide condoms have not shown to provide any more or less function in contraception, but in fact, may increase adverse effects such as irritation and increased urinary tract infections in females.

Consistent or perfect (correct) use of condoms provides effective contraception. Pregnancy rates with the correct use of condoms within the first year of use are two in every 100 women. This is a 98% success rate. This compares to intrauterine devices ( greater than 99% success rate), and the withdrawal method (96% success rate). The correct use of condoms consists of using condoms during and throughout every sexual intercourse. With typical use of condoms (i.e., failure to use condoms during every sexual encounter or not using correctly), pregnancy rates can climb all the way up to 18 in every 100 women within the first year of condom use.[9]

Condoms also serve a primary role in the prevention of certain sexually transmitted diseases (STD). Condoms are most effective at preventing STDs which spread from the male urethral orifice such as gonorrhea, chlamydia, trichomonas, hepatitis B, and HIV. Condoms also assist in the prevention of STDs transmitted via the skin and mucosal membranes such as herpes simplex virus, syphilis, Haemophilus ducreyi, and human papillomavirus. Condoms are only effective in preventing STDs by providing a physical barrier, so prevention only occurs from what is being covered by the actual condom.

Besides the physical issues that could affect condom usage, there are also other barriers such as decreased sensation during intercourse, or disruption of foreplay.

When the female partner is taking oral contraceptives, this can give the facade that one does not need to wear a condom. Although this may aid in the contraceptive role, oral contraceptives do not protect against STDs.

There is also the myth that condom promotion will, in fact, increase amounts of risky sexual behavior. Condom education/promotion has not been shown to have any change in the amount of sexual intercourse among teenagers but has been shown to decrease the incidence of STDs among study groups.

Although one would believe that wearing more than one condom may increase contraceptive barrier properties (“double bagging”), this has not shown to be true. In fact, wearing more than one condom may increase friction between condoms which could increase the risk of the condom tearing.

Pregnant females are advised not to have sex or use condoms for at least six months from the time her male partner has shown symptoms of Zika infection or returned from an area where there is known Zika infection. Women who have symptoms indicating Zika infection, or who have returned from a Zika infection area are advised to use condoms for 8 weeks from the start of their symptoms or from when they returned from Zika infected area.