One of the most common questions Rabbis tend to get is about contraception. Specifically a discussion about family planning, and how long one can use contraception for. Before the man has fulfilled his mitzvah of Peru Urvu to avoid doing a Mitzvah Dioressah could be problematic. However, once they have a boy and a girl there is now a mitzvah drbanan of lsheves.
My question is why do Rabbis say this is a question that must be asked, I don’t ask a Rabbi if I should have guests over for Shabbos. What is the difference they are both avoding doing a biblical commandment (one is Hachnosas Orchaim the other peru urvu). I don’t ask my Rabbi if there is a ‘heter’ to avoid visiting my parents for a year to avoid Kivud Av? Why by family planning is there such an emphasis on asking the Rabbi when other mitzvos (which are not time bound) there is no emphasis to ask?
The answer I am looking for should be based on sources why lsheves/pru urvu is more stringent than other Yoreh Deah cases.


Based on the comments this has been added: Since birth control until more recently was highly problematic, from a Halachic standpoint, there was never any questions about using it, unless Pikuach Nefesh it was Assur. In the past few years where the actual BC is not an issue itself, there has been little public talk in terms of Halcahic writings on it. We are left to infer from the writings which we will call the source. This source can be the Rambam as answered by Dov. We don’t paskan by the Rambam if the SA does not concur with the ruling. We have a Gemora as RabbiKaii and Dov wrote. (Besides the Ramchal in his letters disagreeing with this concept) The Shulchan Aruch does not bring this as his opinion.
We are left with the Shulchan Aruch which says if someone remarries he should remarry to a woman who can have children even if has been Yotze peru urevu. We see from this that he is pro having more children if he can. The minhag has always been to ask questions like this to our Rabbis, I shall continue to do so.
I am still hoping someone will be able to help find a source that can help me understand the Halchic (NOT HASHKAFIK) reason why to ask whether one can take a break after being Yotze Pru urvu (+1) when timed mitzvos generally we don’t ask (for example I don’t know anyone who asked a rov how much money they should put away a month for writing or buying a sefer Torah)

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    Many contraceptives are halachically problematic even if the mitzvas aseh won't apply.
    – N.T.
    Commented Feb 20, 2023 at 11:09
  • Besides that not having guests is passive as opposed to contraception which is proactive, maybe one should ask their lor about having guests.
    – אילפא
    Commented Feb 20, 2023 at 12:36
  • academia.edu/41113803/…
    – Double AA
    Commented Feb 20, 2023 at 12:45
  • @N.T. hardly a relevant reason for a special meeting as that could easily be covered in kala classes where we teach many more severe things and trust them to ask if they aren't sure
    – Double AA
    Commented Feb 20, 2023 at 13:00
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    @RabbiKaii I agree with some of your first point about the minhag. the Gemora is not a Halchic source but Hashkvik. I think you are right about not getting a fool proof answer. Thank you for all the sources you did send. And to everyone who took the time to comment and answer! Commented Feb 22, 2023 at 15:19

3 Answers 3


Possibly because of the following:

Rambam in Hilchos Ishus 15:16:

אַף עַל פִּי שֶׁקִּיֵּם אָדָם מִצְוַת פְּרִיָּה וּרְבִיָּה הֲרֵי הוּא מְצֻוֶּה מִדִּבְרֵי סוֹפְרִים שֶׁלֹּא יִבָּטֵל מִלִּפְרוֹת וְלִרְבּוֹת כָּל זְמַן שֶׁיֵּשׁ בּוֹ כֹּחַ. שֶׁכָּל הַמּוֹסִיף נֶפֶשׁ אַחַת בְּיִשְׂרָאֵל כְּאִלּוּ בָּנָה עוֹלָם

Even once a person has fulfilled the Mitzvah of having children, it is a commandment from our Rabbis not to stop having children all the time one has the strength to do so, since for every additional soul in Israel it is like he has built a whole world.

Also note the Minchas Chinuch on the first mitzvah who says that the mitzvah of Peru Urevu differs from other commandments in that it is an ongoing mitzvah and does not have a time limit.

Finally, also refer to the Gemara in Yevamos 63b:

אָמַר רַבִּי אַסִּי: אֵין בֶּן דָּוִד בָּא עַד שֶׁיִּכְלוּ כׇּל הַנְּשָׁמוֹת שֶׁבַּגּוּף, שֶׁנֶּאֱמַר: ״כִּי רוּחַ מִלְּפָנַי יַעֲטוֹף וּנְשָׁמוֹת אֲנִי עָשִׂיתִי״. תַּנְיָא, רַבִּי אֱלִיעֶזֶר אוֹמֵר: כׇּל מִי שֶׁאֵין עוֹסֵק בִּפְרִיָּה וּרְבִיָּה — כְּאִילּוּ שׁוֹפֵךְ דָּמִים, שֶׁנֶּאֱמַר: ״שׁוֹפֵךְ דַּם הָאָדָם בָּאָדָם דָּמוֹ יִשָּׁפֵךְ״, וּכְתִיב בָּתְרֵיהּ: ״וְאַתֶּם פְּרוּ וּרְבוּ״.

Rabbi Asi said: The Messiah, son of David, will not come until all the souls of the body have been finished, i.e., until all souls that are destined to inhabit physical bodies will do so. As it is stated: “For the spirit that enwraps itself is from Me, and the souls that I have made” (Isaiah 57:16). It is taught in a baraita that Rabbi Eliezer says: Anyone who does not engage in the mitzva to be fruitful and multiply is considered as though he sheds blood, as it is stated: “Whoever sheds the blood of man, by man shall his blood be shed” (Genesis 9:6), and it is written immediately afterward: “And you, be fruitful and multiply” (Genesis 9:7). (Sefaria translation and notation)

  • I don't think this is right. We can find a dozen other mitzvot that have special aggada about them. More likely the practice in the OP is just rabbis not wanting to talk about the issue publicly / a political gambit to get people, who otherwise wouldn't have, to take their psakim seriously. (Obviously it's hard to find a source to prove that as these sources are facially appropriate as a reason.)
    – Double AA
    Commented Feb 20, 2023 at 13:02
  • 1/ Thank you for the answer it is in-depth and clear. However, as an Ashkenazi Jew my custom is to follow the Shulchan Aruch over the Ramabm. The Rambam does not reflect the ruling of the Shulchan Aruch. The SA based on Gemora Yevomos says if one needs to marry another wife, one should marry someone who can bear children. The Ramabam brings this as universal Commented Feb 20, 2023 at 14:05
  • 2/ The Minchas Chincuh and the Gemora quoted are both not saying one can take a break for a few years. More then that, this does not answer the question why it would be different by doing Mitzvah of Hachnosas Orchim which we don’t ask rabbi’s despite being a mitzvah that should always be done. Commented Feb 20, 2023 at 14:06
  • @DoubleAA am I wrong in saying your position is anti charedi? I really want to understand why this you think is the reason of having to ask... Please explain... why would so many rabbis need people to take their psak seriously? Commented Feb 20, 2023 at 14:07
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    @fulltimekollelguy What does charedi have to do with anything? Having children is a huge expense/hassle (that's an understatement) and if you want someone to listen to you to do so against their desire, you have to do more than convincing them to spend $20 extra on their lulav.
    – Double AA
    Commented Feb 20, 2023 at 14:57

There are a lot of meta-halachic issues at play. (See the question in general about "why ask a rabbi?".) But from a strict theory-of-halacha angle, one note I've heard is that "not inviting guests" is passive. Any form of birth control (other than total abstinence, I guess) involves taking some action. This could be considered bitul asei -- actively avoiding a "yes-do" mitzvah.

  • Based on this if someone asks me if they can come to my house for shabbos it is a bitul asei (mdioressa BC is Drabnan) to say no? Commented Feb 21, 2023 at 12:27

I think that there are multiple reasons for this phenomenon.

  1. Most people have not learned the sugya of what types of birth control are permissible and in what circumstances. These topics are rarely talked about in public and aren't published in English seforim for the layperson.

  2. The mitzvah of sheves and l'erev al tanech yodecha, makes it that there can be no blanket heter. There is a constant chiyuv.

  3. Moreover, sheves/l'ereve is a mitzvah that is given great importance in halacha. The Gemara in Chagigah 2b uses sheves as a basis for forcing a master to sell a slave. And Tosafos on the spot says that sheves is an even more powerful mitzvah than pru ur'vu. One is allowed to sell a Sefer Torah just to be mekayem sheves/l'erev (see Shulchan Aruch Even HaEzer 1:2, 8 and the Bais Shmuel on the spot). Which does not apply to any other mitzvah other than learning Torah. On the other hand, the mitzvah is only d'rabanan so people are more likely to be mezalzel in it.

The combination of these 3 factors means that there is a great danger that if a shaila is not asked, people will make major mistakes and be oiver on hashchosas zera or bitul sheves. Moreover--as discussed by Rav Moshe in Even HaEzer 4:67--there is a danger of people learning heterim from their friends and applying it to themselves where they shouldn't.

Of course, if you have learned the sugyos yourself and are confident in your ability to pasken for yourself, that is great. You don't need to ask a shaila because you know the answer already.

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