Under normal circumstances, a couple may not use contraception if they have not yet had children, because the mitzva of procreation is an absolute obligation meant to be fulfilled within a certain time frame. Thus, the Sages state (Kiddushin 29b), “Until a man turns twenty, God sits and waits for him to get married. If he reaches the age of twenty and is not yet married, God says, ‘Let his bones swell up!’” because he has not started to fulfill the mitzva of procreation (MT, Laws of Marriage 15:2; section 7 above). Nevertheless, we have seen (section 9) that in our times, one may delay marriage, when necessary, until the age of 24. Those who are privileged to marry earlier may not actively avoid fulfilling the mitzva of procreation.
Only when there are extenuating circumstances, such as when the wife suffers from physical or mental illness, is it permissible for newlyweds to use contraception even before her first pregnancy, so that she can get healthy. This permit should be granted only after serious deliberation and after consultation with a God-fearing doctor.
Similarly, if a couple’s relationship is shaky and there is concern that they will have to divorce, they should avoid pregnancy until their relationship is stable. This permit is generally for the period of six months to a year.
There is another reason to consider a couple’s circumstances to be pressing: when both are enrolled in particularly rigorous academic frameworks, such as medical school. If no one is available to help them, and in their estimation, getting pregnant and having a baby would mean that at least one of them would need to drop out of school and lose the opportunity to realize their aspirations and develop their talents in a profession that suits them so as to contribute to society, then since pregnancy and birth would cause them considerable and lasting harm, they may use contraception, as these are pressing circumstances. This is on condition that using contraception will not prevent them from fulfilling the mitzva of procreation by having four to five children (as explained above in section 6). The situation needs to be examined seriously by a wise rabbi.
Let us say a young couple is in a serious relationship and are planning to get married, and they ask whether it is preferable to get married and use contraception until they finish their professional schooling, or postpone marriage. Then even though their halakhic obligation is to get married and not use birth control, nevertheless, if these are the only two options they are willing to consider, it is better that they get married and use contraception. By delaying marriage, they will be delaying the fulfillment of the mitzva of ona, and will also be prone to having sinful thoughts.
Under pressing circumstances, contraception can be permitted for the completion of a particularly demanding course of study, such as medicine, since without contraception, there is a reasonable concern that one of the spouses will not be able to realize their dreams, causing significant, lifelong harm. The grounds for this permit are twofold. First, we can extrapolate from the Sages’ permission to postpone marriage until the age of twenty to allow a man to study Torah and train for a profession. Yam Shel Shlomo and Birkei Yosef comment that if truly necessary, it is permissible to delay marriage until the age of 24, as explained above in section 9 and n. 7. Beit Shmuel 1:5 states that whereas Rosh limits the postponement of marriage even when there is a good reason, Rambam implies that someone immersed in Torah study may postpone marriage longer as long as his sexual drive does not overpower him. Stretching this point, a similar allowance might be made for someone who is studying a demanding subject for the sake of heaven and in order to better the world, and he would not be able to complete his studies without relying on contraception. This is comparable to the permission given above (section 9) to postpone marriage until the age of 24 for the sake of studies and other very important pursuits. (The opinion of Responsa Rashba 4:91, that there is no Torah obligation to get married by a certain age, cannot be used here as an additional factor, because the Sages do require marriage by a specific age, as explained in n. 7.)
Second, halakha does not demand that a person spend more than a fifth of his assets to fulfill a mitzva (Rema 656:1). Only if the going price for a mitzva item exceeds one fifth of his income must he spend more. Nevertheless, if it is possible to fulfill the mitzva at a later point, one might suggest that halakha does not demand that a person give up his dream, when it is worth more to him than a fifth of his assets. Furthermore, this type of sacrifice usually entails losing much more money than a fifth of one’s income. It is also important to point out the value of making a living. The Sages did not demand that camel-drivers and sailors quit their jobs even though they needed to travel for as much as six months at a time, thus reducing the chance that they would fulfill both the Torah and rabbinic obligations to procreate.
However, the permit is limited to pressing circumstances and where there is no other option. It is proper to consult with a wise rabbi who understands all the different aspects of this issue in order to examine whether contraception is necessary to allow them to realize their dreams.
As we have seen in section 7, the Sages prohibit delaying marriage beyond the age of twenty, for two reasons (Kiddushin 29b): First, according to the academy of Rabbi Yishmael, because it neglects the mitzva of procreation. Second, according to Rav Huna, because of sinful thoughts and, formulated positively, because of the value of marital love as expressed in the mitzva of ona. We see that even if a person avoids fulfilling the mitzva of procreation, there is nevertheless a mitzva for him to get married, both to fulfill the mitzva of ona and to avoid sinful thoughts. Thus, when a couple insist that they must either put off marriage or use contraception, it is preferable for them to marry and use birth control.