This is a link to where the church stands on birth control: Birth Control Basically, it is a prayerful decision to be made between husband, wife, and the Lord. As it is with all major decisions in life. The church can't make an official stand on every single little controversial thing, because that would frustrate the need for personal revelation. However, this is on lds.org, so I think it's official enough :) As for what past prophets have said... Well, look at polygamy. It was a commandment of the Lord to certain men in the 1800's, and then there was not a need for it anymore, so the "policies," if you will, changed. Polygamy is not only unnecessary, it is unlawful in today's world. Look at the Law of Moses. It was the law, the set of commandments, for a very long time. When Christ came, the law was fulfilled, and new laws were enacted. The church can change policies with the times, not only is this ok, but it is necessary! If we never changed modesty codes from the 1800's, we would still be having to cover wrists and ankles, and females would only be allowed to wear dresses. The church policies change, but the main doctrine, the scriptures and the current prophet's teachings, are still truth. Pres. Ezra Taft Benson said this: "The most important prophet, so far as we are concerned, is the one who is living in our day and age. This is the prophet who has today's instructions from God to us today. God's revelation to Adam did not instruct Noah how to build the ark. Every generation has need of the ancient scripture plus the current scripture from the living prophet. Therefore, the most crucial reading and pondering which you should do is of the latest inspired words from the Lord's mouthpiece." Also said, in multiple different manuals of the church, are these statements, referring following modern prophets and parenthood: "As far as we are concerned, which prophet is as important as Moses, Abraham, Nephi, or any other ancient prophet? (The current prophet, because he is directing us today.)" "Why do you think many people have a tendency to respect ancient prophets, those in the Bible for instance, more than those living today? (People tend to be more critical of the human faults of those who are still living.)" "President [spencer W.] Kimball said, 'It is an act of extreme selfishness for a married couple to refuse to have children when they are able to do so.' When married couples postpone childbearing until after they have satisfied their material goals, the mere passage of time assures that they seriously reduce their potential to participate in furthering our Heavenly Father's plan for all of his spirit children. Faithful Latter-day Saints cannot afford to look upon children as an interference with what the world calls 'self-fulfillment.' Our covenants with God and the ultimate purpose of life are tied up in those little ones who reach for our time, our love, and our sacrifices." "How many children should a couple have? All that they can care for! Of course, to care for children means more than simply giving them life. Children must be loved, nurtured, taught, fed, clothed, housed, and well started in their capacities to be good parents themselves." You take it for what it's worth :)
