Q: Should Genesis 1:28, be used as a reference against birth control? If birth control is permitted, does it depend on the motive?”
A: “Be fruitful and multiply and replenish the earth” does not completely close discussion on the matter of birth control. It does, however, speak strongly against those who enter into marriage today and do not view children as a blessing, and thus practice birth control for selfish and possibly materialistic reasons. God has said that “children are an heritage of the Lord” (Ps. 127), but he has not specified that this means every married, child-bearing aged woman is to seek prayerfully and physically a pregnancy every nine months. When the Lord permits children to be born into Christian homes, we can trust that he will provide the wherewithal to meet the basic needs (Matt. 6:33); yet, God has also given man and woman an intellect to use for making prudent, prayerful decisions that will take into consideration concerns of health and well-being. Peter urges husbands to treat their wives “according to knowledge” (I Pet. 3:7). This would include possibly having to practice sexual restraint at times for the health of his wife.
No doubt someone may wish to raise the incident of Onan and Tamar in Genesis 38 as an objection to all birth control. Although we are told that what Onan did was “wicked in the Lord’s sight,” we would be hard-pressed to draw the conclusion that any time the husband’s “seed” is kept from entering the wife’s reproductive system it is to be considered a sin. Onan’s case was specific. The practice of levirate marriage (v. 8, and later as law: Deut. 25:6) was being observed at his time, and he knew it, but shunned his responsibility anyway.
If birth control is used (i.e., for a health reason), then is only a natural method to be used, such as withdrawal or the rhythmic system, or can certain artificial means be used? A number of our Lutheran theologians in the past limited birth control methods only and this only in the most rare cases. (See, for example, an extended discussion on this by Dr. J. Fritz in his book, Pastoral Theology, pp. 176-179.) It should be remembered, though, that much of the objection to artificial contraception was to avoid abortifacient means of controlling births. Today, too, even if certain artificial means may be used by spouses according to sanctified Christian judgment, any abortive devices would be abhorred and forbidden by the Lord. An example of such devices are the IUDs, or intra-uterine devices. The high regard for every life in the womb, no matter what stage of life it is in, ought to be of supreme importance (Ps. 139:13-16) and should not be interfered with, unless the mother’s life is obviously endangered. For this reason, Christian spouses will want to ask Pro-Life doctors very serious questions about contraceptives before they quickly subscribe to any one method.
In the final analysis, you are right in suggesting that “motive” is a vital factor in the rightness or wrongness of utilizing birth control. It is unfortunate that many let society’s humanistic and self-centered attitudes influence their decisions in this regard, without first considering what God has said on the blessedness of children. Admittedly, not all married couples are able to have children. This is in the providential realm of our all-wise God who still brings blessings amid our crosses. But one of the major purposes of the God-ordained institution of marriage, namely, procreating and bringing up young souls in the ways of the Lord, cannot be overlooked. Before hastily deciding on birth control, every Christian spouse will want to note these words from Paul: “And whatever you do, whether in word or deed, do it all in the name of the Lord Jesus, giving thanks to God the Father through Him” (Col 3:17).