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They are also known as prophylactics and rubbers.
The first clumsy efforts at making condoms involved the use of woven fabrics. These were obviously not effective. The earliest effective condoms were made of sheep gut or other animal membrane. These are still available today because of their ability to transmit body warmth and tactile sensation, but they are not as effective in preventing pregnancy and disease as synthetic condoms. When latex condoms were finally available, it was a big step forward in effectiveness and affordability. However, before the middle of the 20th century, many places outlawed the sale of condoms, and many subsequently allowed their sale "only" "for the prevention of disease."
Latex condoms are packaged in a rolled-up form, and are designed to be applied to the tip of the penis and then rolled over the erect penis. They have a "right side" and a "wrong side" when rolled up, and the first thing the user must do is to determine which side is which before attempting to apply them. Any touching of the penis to the "wrong side" of the rolled-up condom before application potentially contaminates the outside with sperm-bearing fluid, and in this case the condom should be discarded and another condom used.
The early latex condoms were pretty much all the same, except that some eventually came to have reservoir tips to contain ejaculated fluid. One relatively early innovation, the "short cap", only covered the head of the penis. These were a dismal failure in reducing disease and pregnancy.
In recent decades, however, manufacturers have produced a variety of sizes, colors, and shapes of condoms, including ones that are flavored and ones that are supposed to have stimulating properties. Such stimulating properties include enlarged tips or pouches to more easily accommodate the glans penis and textured surfaces such as ribbing or studs (small bumps). Many condoms have spermicidal lubricant added, but it is no substitute for separate spermicide use.
Condoms made from natural materials (such as those labelled "lambskin", made from lamb intestines) are not as effective at preventing disease. A few companies are today also making condoms from polyethylene and polyurethane, which are expected to be as effective as latex but which have not had as much testing. The alternate materials are useful for those who are allergic to latex.
Recently "female condoms" (or femdoms) have become available. They are larger than male condoms and have a stiffened ring-shaped opening, and are designed to be inserted into the vagina. The female condom also contains an inner ring which keeps the condom in place inside the vagina - inserting the female condom requires squeezing this ring. Sales of these have been disappointing, however, so they are not as widely available as they were at first. Probable causes for poor sales are the fact that inserting the female condom is a skill that has to be learnt which solitary males cannot practice in advance, as well as reported "rustling" sounds during intercourse. This type of condom is made from polyurethane.
As a method of contraception, condoms have the advantage of having virtually no side-effects, and of offering protection against sexually transmitted diseases. There is a paradox in the use of condoms for contraception: their theoretical effectiveness is relatively high, but their actual effectiveness is relatively low. This is because many people fail to rigorously follow the proper procedures for condom usage. Even touching the female genitalia with the same (unwashed) hand that removed the condom can potentially cause pregnancy. Furthermore, surveys have shown that many users do not know how to correctly put them on, resulting in bursts and slippages.
So, of themselves, condoms are only moderately reliable, but when combined with a spermicide their reliability is comparable to other methods of contraception. Their disadvantage is that some people find them unpleasant, especially because they eliminate skin contact and reduce sensitivity, and that putting them on can interrupt lovemaking. Most failures are due to misuse. This has led some researchers to ask for earlier and more explicit sex education, but such efforts are fought by religious groups campaigning against premarital sex, who feel that explaining the use of condoms and other contraceptives to youngsters encourages such behavior. Condoms are for single use only.
The use of prophylactics involves the following:
Some men who feel a particular size condom is hard to put on because it is too small have reported that they partly unroll the condom, stretch it with both index fingers, insert the penis (asking their partner to expel air from the tip), remove fingers and unroll. German language pictorial instructions. This procedure is not recommended as ones nails can come in contact with the condom. Consider buying a larger condom, or practising the approved method above.