The church position is that it is a sin to have sex outside of marriage and within marriage it is a sin to use artificial means to prevent conception. The only natural means accepted is abstinence; however, they consider the rhythm method of birth control (only having relations when pregnancy is unlikely) to be a form of abstinence.
The church has softened its position somewhat. They recently stated that sometimes contraception is the "lesser evil" in situations where one partner has AIDS or if pregnancy would be life threatening for the mother or if a family is in danger of starving with another mouth to feed. The church does still consider it a sin to use counterception to limit your offspring for reasons such as convenience or in order to enjoy a higher standard of living. Catholic couples are expected to bring as many Catholic souls into the world as they possibly can.
Catholic churches regard sex outside marriage as morally wrong (or if not wrong, as less than good), they believe that abstaining from sex would be morally better than having sex and using birth control.
More conservative churches suggest that contraception should be limited to married couples who are using it to regulate the size and spacing of their family. They often teach that using contraception to prevent children altogether is not desirable.
The Roman Catholic Church only allows 'natural' birth control, by which it means only having sex during the infertile period of a woman's monthly cycle. Artificial methods of contraception are banned.
They are pretty much against using artificial medicine i guess..
The official position of the Catholic church as stated in the catechism is basically that love should have the possibility of producing children. Which I think is a bit stupid, and I am Catholic. Firstly, does this mean that an infertile couple have no right to have sex? And secondly, contraceptive is not 100% effective, therefore there is still the possibility, albeit a reduced one. But I think if God really wanted someone on contraceptive to have a child he would find a way around it!
To add to danielle, when it is done outside of marriage, and without the possibility of children, it is seen as a corruption of the act. This is why other se xual practices are frowned upon such as @nal sex. Ma.sturb@tion is also frowned upon as there is no relational aspect between spouses.