Members of The Church of Jesus Christ of Latter-day Saints, often mistakenly called the “Mormon Church,” are known for having large families. Doctrines of the Church of Jesus Christ make Mormons want to bring children into their homes, but Mormons do practice birth control.
Leaders of the Church of Jesus Christ counsel members not to put off and not to prohibit children from being born into their families for worldly reasons. An example would be not to have children until you have a house, or are finished school, or have finished all the traveling you desired. Many young husbands and wives in the Church have accepted this counsel and are still in school when their first few children are born.
The Plan of Salvation as revealed to ancient and modern prophets tells us that we are all eternal beings. Before we began our mortal lives on earth, we lived with God as His literal spirit children. Mortality is the next step in our progression to become more like our Heavenly Father. Mormon parents have a lot to offer God’s spirit children—a life of spiritual abundance, a secure sanctuary of a home, stability, security, and the presence of the priesthood power from God. Thus, they should be ready to welcome as many spirits into their home as possible.
That said, birth control is between a husband, a wife, and God. How many children they have and when is up to them. Mormons are prayerful about these important decisions, and they are privy to personal revelation when they seek guidance about child-bearing. The following statement is from a book called True to the Faith, a Gospel Reference.
When married couples are physically able, they have the privilege of providing mortal bodies for Heavenly Father’s spirit children. They play a part in the great plan of happiness, which permits God’s children to receive physical bodies and experience mortality.
If you are married, you and your spouse should discuss your sacred responsibility to bring children into the world and nurture them in righteousness. As you do so, consider the sanctity and meaning of life. Ponder the joy that comes when children are in the home. Consider the eternal blessings that come from having a good posterity. With a testimony of these principles, you and your spouse will be prepared to prayerfully decide how many children to have and when to have them. Such decisions are between the two of you and the Lord.
As you discuss this sacred matter, remember that sexual relations within marriage are divinely approved. While one purpose of these relations is to provide physical bodies for God’s children, another purpose is to express love for one another—to bind husband and wife together in loyalty, fidelity, consideration, and common purpose. 
The wisdom of God is manifest in these paragraphs. Intimacy between husband and wife is sanctioned by the Lord, and matters of childbirth are between them and God.
Abortion is another matter entirely and is wholly condemned by the Church of Jesus Christ. It is considered next to murder in its seriousness as a sin, and even in cases of incest, rape, and danger to the life of the mother, should be undertaken only when absolutely necessary. Following is the counsel regarding abortion:
In today’s society, abortion has become a common practice, defended by deceptive arguments. If you face questions about this matter, you can be secure in following the revealed will of the Lord. Latter-day prophets have denounced abortion, referring to the Lord’s declaration, “Thou shalt not … kill, nor do anything like unto it” (Doctrine and Covenants 59:6). Their counsel on the matter is clear: Members of The Church of Jesus Christ of Latter-day Saints must not submit to, perform, encourage, pay for, or arrange for an abortion. If you encourage an abortion in any way, you may be subject to Church discipline.
Church leaders have said that some exceptional circumstances may justify an abortion, such as when pregnancy is the result of incest or rape, when the life or health of the mother is judged by competent medical authority to be in serious jeopardy, or when the fetus is known by competent medical authority to have severe defects that will not allow the baby to survive beyond birth. But even these circumstances do not automatically justify an abortion. Those who face such circumstances should consider abortion only after consulting with their local Church leaders and receiving a confirmation through earnest prayer.
When a child is conceived out of wedlock, the best option is for the mother and father of the child is to marry and work toward establishing an eternal family relationship. If a successful marriage is unlikely, they should place the child for adoption, preferably through LDS Family Services. 
A person who participates in an abortion can face church discipline.
LDS Family Services provides adoption help for unwed mothers who cannot or will not marry the fathers of their babies. This service is a loving way to help infertile couples in the Church bring children into their homes. Unwed mothers who give up their children can be assured that every blessing that can be provided in a good LDS home will come to their children. LDS adoption services have a special website, It’sAboutLove.org. Help and guidance are available for unwed mothers and fathers, their parents, and adoptive parents. Following is the statement on adoption from True to the Faith:
Children are entitled to be raised by parents who honor marital vows and who provide love and support. Adoption can be a great blessing for many children who are born without this opportunity.
When a child is conceived out of wedlock, the best option is for the mother and father of the child to marry and work toward establishing an eternal family relationship. If a successful marriage is unlikely, they should place the child for adoption, preferably through LDS Family Services. Placing the infant for adoption through LDS Family Services helps unwed parents do what is best for the child. It ensures that the child will be sealed to a mother and a father in the temple, and it enhances the prospect for the blessings of the gospel in the lives of all concerned. Adoption is an unselfish, loving decision that blesses the birth parents, the child, and the adoptive family.
If you are married and you and your spouse want to adopt a child, be sure you know all legal requirements of the countries and governmental agencies that are involved. Counsel with your priesthood leaders and, if possible, with staff members in LDS Family Services. If LDS Family Services is not available in your area, work with your priesthood leaders to locate licensed, authorized agencies that protect both the children and the adoptive parents.