The bible emphasizes stewardship
Sometimes we tend to make the birth control issue a "sin" issue but the bible emphasizes stewardship when it comes to the topic of procreation. God repeatedly makes it a point that children and life are a gift from Him. Our responsibility is to steward the gift of life well. This also includes our own life, our spouse's life and the livelihood of the family unit as a whole.
Stewarding the family well requires wisdom, love and the ability to weigh every individual situation righteously. What may be right for one family may not be the most prudent solution for another family's specific circumstances.