By: Rabbi Ari Enkin
There is a mistaken impression in the orthodox community that there is a halachic requirement to continue to have children indefinitely. This notion is based primarily on the following Talmudic passage which is also the main source for discussions on family planning and related issues:
Rabbi Yehoshua said “Even if a man married a woman in his youth, he should marry again in his old age. If he had children in his youth, he should also have children in his old age, as it is says "sow your seed in the morning and do not rest your hand in the evening (vela’erev al tanach yadecha)". For you do not know who will prove worthy, whether these children or those, or whether both will be equally good.”Click here to read moreIt is specifically the injunction of “do not rest your hand in the evening” (“la’erev”) which is widely cited as the source for the requirement that a couple continue to have children even after fulfilling the Torah's mitzva of procreation by having one boy and one girl. With the noted exception of the Rambam, all of the prominent early authorities ("rishonim") rule that the rabbinical enactment to continue to have children is not as binding as the other rabbinical enactments which we are accustomed to. As Rashi writes: "…there is somewhat of a mitzva to continue to have children." So too the Ramban writes, "…[continuing to have children in one's old age] is a mitzva l'chatchila but we don’t force a person to do so, nor do we call him a sinner if he chooses not to."
Even the Rambam, who is of the opinion that the mitzva to have children continues indefinitely, qualifies his ruling with the stipulation that it is only binding "as long as one has strength". He does not define or qualify what exactly "as long as one has stenght" is, which makes it subject to interpretation. It is worth noting that even the Shulchan Aruch does not follow the opinion of the Rambam.
Therefore, as with all controversies in rabbinic law, one is entitled to follow a lenient interpretation regarding continuing to have children, especially when there are difficutlies in comfortably doing so. This is true even when marrying for a second time. Furthermore, Rabbi Henkin argues that even the rabbinical injunction ("vela'erev") to continue to have children is itself limited in nature and may only have been intended to parallel the Torah's requirement of having children. As such, the entire scope of "vela'erev" might only require repeating the Torah's requirement to have a son and a daughter. Once this is fulfilled (i.e. two girls and two boys), a couple would be permitted to cease having children entirely without concern for violating any rabbinical injunction whatsoever, should they choose to do so. It follows, therefore, that continuing to have children after fulfilling the requirement to procreate is an optional, albeit commendable, mitzva for those who are able to do so.
Based on the above, Rabbi Henkin permits a couple to practice family planning in a number of situations. This includes concerns relating to shalom bayit, and by extension, the ability for a family to function efficiently with additional children. A classic precedent for allowing family planning on the basis of shalom bayit can be found right on the pages of the Shulchan Aruch. The Rema cites a case where the Terumat Hadeshen was asked concerning a widower who wanted to marry a certain woman but was afraid that fights would break out between his children (from his first wife) and the woman's children. In the end, he decided against the idea and instead married a woman who was infertile but not likely to clash with his children. The Terumat Hadeshen ruled that the man's decision was an acceptable one, as the need to ensure shalom bayit takes precedence over the requirement to have more children. Similarly, a couple should not fight if one spouse prefers not to have more children. The dispensation to allow family planning for shalom bayit considerations also includes financial and economic factors, including the inability of a woman to work when a second income is necessary.
There are also exemptions from any duty to continue to have children based on health concerns and birth defects, such as Down syndrome. As the Yam Shel Shlomo writes: "a woman may use a contraceptive if she has distress in childbirth or is afraid of having children who are unworthy ("ainum hagunim" – referring to birth defects)…." This even includes a concern that one's children will stray from the path of Torah. As the Yam Shel Shlomo concludes "…all the more so, if her children have strayed from the proper path and she is afraid of producing more such children, she is permitted to prevent conception.” This might be true even for those who did not yet fulfill the Torah's requirement of procreation.
Closely related to dispensations based on health concerns is Rabbi Henkin's position on permitting women to practice contraception for one year or more after giving birth in order to allow them to fully recover from childbirth. This was the position of the Chazon Ish, as well. Furthermore, Rabbi Henkin will often allow contraception for up to two years or more if a woman feels that she needs to take a break in between children in order to devote her time and energy to raising her baby. This is true even if the couple has not yet fulfilled the Torah's requirement of procreation. This is because spending one's time focusing on and raising one's children in the spirit of the Torah is perhaps the greatest expression of procreation! Hence, even though a woman might be preventing conception for these two or more years, she is actually not evading the mitzva of procreation at all.
It goes without saying that painful, risky, and complicated pregnancies are also included in the umbrella of health concerns, especially if the couple has already fulfilled the Torah's requirement of procreation, and often even if they haven't. In order not to unnecessarily delay marriage, Rabbi Henkin will permit newlyweds to use contraception for up to the first six months of marriage if they feel that they are not yet ready for children. This is especially true for newlyweds under the age of twenty. Nevertheless, one should not criticize those who practice contraception for several years after marriage. Rabbi Henkin's preferred contraceptive method is the diaphragm along with the accompanying foams.
This paper is based on my understanding of Bnei Banim 1:30, 1:31, 2:38, & 4:15. E&OE
 Yevamot 62b
 Kohelet 11:6
 Rambam Ishut 15:16
 Beitza 37a
 Milchemet Hashem;Yevamot 62b
 E.H. 1:8
 Rema E.H. 1:5
 It is interesting to note that even Rabbi Moshe Feinstein allowed contraception for financial considerations. As he writes in Igrot Moshe E.H. 4:72:…"if they have already fulfilled the mitzva of procreation and there is an economic reason or other pressing need, or even
if they have not fulfilled the mitzva but the woman is weak, she may take
birth control pills.”
 For more on family planning in situations of Down Syndrome and other birth defects, including the permissibility of aborting, see Tzitz Eliezer 14:101, 13:102
 Yam Shel Shlomo;Yevamot 6:24