It would be dishonest not to admit that there is some disagreement within the Church over the issue of conception control. Some of those heavily influenced by monasticism tend towards a more negative almost Augustinian view of sexuality. Therefore, they tend to oppose all use of birth control. Others, have what I consider a proper Orthodox view that considers sex good because it is part of God's creation. However, like everything else created by God we can abuse God's creation. If sex becomes exploitative, or if a man treats his wife as a sex object, or a woman treats her husband as a sex object it is morally wrong even in marriage. Furthermore, every sexual relationship must be within marriage and most be open to the creation of new life. That does not mean that every sexual act between a married couple has to be open to the creation of new life, but the relationship must be open to the gift of children. Thus, a couple may use non-abortive methods of birth control to space the birth of their children, if the couple has had all the children they can care for, and if a further pregnancy would endanger the health of the woman. I also think that a newly married couple should use birth control for a few years so that they can get to know each other, finish their educations and be properly prepared to care for a child.
I believe that there is no calling from God that is superior to any other calling. Some of us are called to monasticism, but most of us are not. A good pious and dedicated married layman who is serving God to the best of his ability is serving God in the highest calling possible for him and is not spiritually inferior to a monk or priest. For God's Church to function, we need monastics, clergy serving parishes in the world and laity. We are all essential to the life of the Church. If there were no married couples, there would be no monks or nuns.
Fr. John W. Morris