Let me add the LDS perspective to this question.
The Church of Jesus Christ of Latter Day Saints generally opposes abortion and birth control but for different reasons. Abortion - and SOME forms of birtth control - actually terminate a life that has begun (however tenuously). We object to abortion on those grounds, but we do recognize that in cases of rape, incest or danger to the mother abortion may be an option.
Birth control is considered a sin, but for a different reason. We have no problem with the idea of sex "fer fun." We do, however, believe that the Lord has commanded us to "be fruitful and multiply." We also believe - uncommon in the Christian world - in the idea of a "pre-existence." We believe that there are babies up there just waiting to be born. Our duty is to bring them to this world. The whole reason we exist on this earth is to have families. Consequently, birth control solely for the purpose of not having children is considered a sin of ommission. The church, in its "Proclamation on the Family" does leave wiggle room for responsible family planning, but permanent sterilization would normally only be considered appropriate in case of medical necessity.
Part of the reason for the ambiguity on the issue of birth control is that methods - and therfore situations - differ. For example, some faiths have no problem with the "rhythm method" since there is no life potentially created. (Of course we all know what they call people who use the rhythm method - parents!) Under our philosophy, that issue is moot. Birth control even under non-abortive circumstances is discouraged. But something like a "morning after" pill or certain IUD devices are intended to keep a fertilized egg from attaching to the uterine wall. That means a potential life is ended. So condoms, yes - if necessary - but IUDs, no.
Incidentally, in case anyone wonders, nobody is going to get excommunicated from the LDS church simply for using birth control. Like many things, it is a matter of personal choice, but it is discouraged. Even unwarranted abortion is amenable to forgiveness - though it is considered among the most serious offenses against God.