Condoms are a common form of birth control. One of the advantages of condoms is that they can help prevent sexually transmitted diseases. Condoms have the disadvantages of; (1) not always being available when you want them, (2) reducing sensitivity which for some men impairs enjoyment, (3) sometimes failing by breakage or leak, (4) interrupting the smooth flow of the sexual interaction. Condoms have an average effectiveness in common use of 86% (meaning that of 100 couples relying on condoms for birth control, 14 will be pregnant within a year).