Contraception is the practice of reducing the likelihood that coitus will result in procreation. No form of contraception entirely removes this possibility.
Some religious denominations - notably the Catholic Church - regard contraception as immoral, claiming that it contradicts God's commandments to "Go forth and multiply." Genesis 9:7 This has lead to controversial announcements in opposition to the use of condoms to prevent the spread of AIDS in Africa and to lift from the impoverished the curse of progeny whom they cannot support.
Judaism allows for certain types of contraception that do not "waste the seed" of male ejaculation.  This is based on the story of Onan and coitus interruptus:
"And Onan knew that the seed would not be his; and it came to pass, when he went in unto his brother's wife, that he spilled it on the ground, lest he should give seed to his brother. And the thing which he did was evil in the sight of Jehovah: and he slew him also."
Christian views are often shaped by the idea that the primary purpose of sex is procreation.
There is a diversity of views on contraception within protestantism, ranging from acceptance to strong opposition. A major shift in Anglican views occurred in the 1930 Lambeth Conference:
- "Nevertheless in those cases where there is such a clearly felt moral obligation to limit or avoid parenthood, and where there is a morally sound reason for avoiding complete abstinence, the Conference agrees that other methods may be used, provided that this is done in the light of the same Christian principles. "
This was the start of a general shift of other mainstream protestant denominations towards acceptance of contraception.
The only permitted form of contraception allowed in Catholicism are calendar based methods, such as the rhythm method or natural family planning (NFP).
- "If there are well-grounded reasons for spacing births, arising from the physical or psychological condition of husband or wife, or from external circumstances, the Church teaches that married people may then take advantage of the natural cycles immanent in the reproductive system and engage in marital intercourse only during those times that are infertile, thus controlling birth in a way which does not in the least offend the moral principles which We have just explained…. When the infertile period recurs, they use their married intimacy to express their mutual love and safeguard their fidelity toward one another. In doing this they certainly give proof of a true and authentic love. "
- "The Catholic Church supports the methods of Natural Family Planning (NFP) because they respect God's design for married love. "
If calendar based contraception is effective, there is no logical reason for it to be treated differently from other contraceptive methods. If Calendar-based contraception is not effective, the church should not be recommending it as a method of contraceptive. However, the church only permits sex if a child is wanted at some point in the future, so some failures would lead to an earlier than desired but not an unwanted pregnancy. Evidence suggests that this method is 75% effective over the course of one year, which is worse than most other contraceptive methods.  Effectively, the church has a different idea of what a contraceptive should be: calendar-based contraception is allowed because it is unreliable! The church justifies NFP based on the naturalistic fallacy and dogma about being "open" to life.
- "In the first case, one does something (takes a pill, uses a condom, etc.) to deliberately "close" the life-giving power of sexual intercourse. In NFP, however, no such step is taken. The spouses do not act against their fertility. "
The Affordable Care Act originally mandated that non-religious organisations that provide health insurance to employees must include contraception. In 2014, the supreme court ruled that "closely held" family controlled corporations may choose to deny provision of contraceptions under health insurance provided to employees on the grounds of religious freedom. The dissenting supreme court judges wrote:
- "In a decision of startling breadth, the court holds that commercial enterprises, including corporations, along with partnerships and sole proprietorships, can opt out of any law ... they judge incompatible with their sincerely held religious beliefs "
Companies that are largely owned by non-managing shareholders are still required to provide contraception under the Affordable Care Act. Religious organisations are already exempt from the law.
Muhammad was said to be aware of his followers' use of contraception (coitus interruptus). He did not forbid the practice, therefore contraception is generally considered to be allowed by Muslims.   However, sterilization is generally not allowed by Islam.
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- ↑ Lawrence Hurley, U.S. justices uphold firms' religious objections to contraception, Jun 30, 2014
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