I am a teacher at a private all-girls Jewish high school. There are two science teachers in the school, and both of us are Christian. I was talking with my fellow science teacher recently, and she mentioned that during a discussion in her human anatomy and physiology class her students brought up that they had learned in one of their religious classes that, if a baby was to be born prematurely, it is better for a baby to be born eight weeks early, for example, rather than six weeks early because the lungs are stronger at 32 weeks gestation than they are at 34 weeks gestation . Obviously, this is contrary to scientific knowledge, but we don't want to trample all over our student's religious beliefs and teachings. Thus, we are unsure of how to respond to the girls in this instance. There are only a couple of things I can think of for this type of discrepancy:

  1. The particular text they were studying might have been written at a time when very little was understood about human anatomy and reproductive health in general. I can't recall exactly which class this was discussed in (bekius maybe?). I am under the impression that it was a rather old text, though not a Biblical text.
  2. The girls perhaps misinterpreted the text. I believe they understood the words they were reading, but I wonder if they perhaps missed the point of the text--sort of like reading Shakespeare and getting hung up in the language.
  3. This is exactly what the author meant and the girls interpreted it correctly.

So... A) Is anyone familiar with the text this comes from? B) If so, could you please clarify the interpretation with supportive context such that I can sort of understand it?

Thank you so much for your help!

  • 3
    Meg, welcome to Mi Yodeya, and thanks very much for this excellent question! I hope you'll continue to use this site as a resource for helping you understand more about your students.
    – Isaac Moses
    Mar 6, 2013 at 4:09
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    Meg, I just came across this concept in Tractate Shabbath as part of the Daf Yomi cycle, and it seemed rather odd to me. I mentioned it to someone who has never learned it before in this Talmudic (or probably any religious) context, and they were adamant that they had heard or read something to support this from a scientific perspective. In fact, the Talmud doesn't mention anything about the lungs, but this was the reason given to me by this person. The reason I mention this is that you say it is obviously contrary to science. I would have thought so, too. But can you back up that claim?
    – Seth J
    Mar 6, 2013 at 4:32
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    @CharlesKoppelman, so not only does the Talmud contradict now-known science, so does an urban myth. Great.
    – Seth J
    Mar 6, 2013 at 4:44
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    @Ariel In his earlier comment he heard a rumor about how the Talmud's rule is actually supported by modern science. Turns out apparently this was false.
    – Double AA
    Mar 6, 2013 at 5:32
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    Thank you all for your fantastic responses! It has really clarified for me what the girls were studying to bring about their questions, and I think it will help both myself and my fellow teacher formulate a good reply to our students--certainly in this case, but also in future cases if they arise.
    – Meg Coates
    Mar 6, 2013 at 14:35

3 Answers 3


This is from the Babylonian Talmud. Shabbat 135b says that we don't break Shabbas to save the life of a baby born in its eighth month of gestation. The idea was that there are 7-month babies and 9-month babies, and an 8-month baby was either an early 9-monther or a late 7-monther and if it were an early 9-monther, it probably wasn't going to make it.

Here is a great documentation of different viewpoints on this issue today (search for the section labelled "Premature Babies"). It says:

As we already mentioned, the Talmud claims that babies born in their eighth month from conception are not viable [and thus you cannot help them live on Shabbat]. The Chazon Ish (Yoreh Deah 155:4) explains that the sages observed that babies born in their seventh month rarely survived. However, a small but significant percentage lived. In the eighth month, the survival rate dropped even lower. But in the ninth month, the survival rate rose sharply. This phenomenon is reflected in other ancient medical works such as those by Hippocrates and Galen (see J. Preuss, Biblical and Talmudic Medicine, 14:14)....

With all this in mind, we can understand the following from Tosefta Shabbat 16:4.

Who is an eight-month [baby]? Any [baby] who has not completed his months. Rebbe says: His signs identify him - his hair and fingernails... Rabban Shimon ben Gamliel says: Whoever has lasted thirty days is not a stillborn...

According to the first anonymous opinion, any baby born in its eighth month, i.e. who has not completed its nine-month development period, is considered to be an eight-month baby that will not survive. According to Rebbe, only a baby that is born in its eighth month and is not developed enough to have fingernails and hair is considered to be an eight-month baby. Even if a baby is born in its eighth month, if it is fully developed it is deemed viable and treated appropriately. According to R' Shimon ben Gamliel, any baby that survives its first thirty days is deemed viable. [Other opinions are noted....] Regardless, the Shulchan Aruch (Orach Chaim 330:7-8, Yoreh Deah 266:11) rules that a baby born in its eighth month that has fingernails and hair is considered viable in regard to the laws of Shabbat. What is significant is that the rabbis recognized that a baby born in its eighth month can live a full and long life. However, based on their observations and medical knowledge, they said that the overwhelming majority does not.

The article goes on to explain how various folks on the right-wing of Judaism understand the text nowadays. Some people claim nature has changed. Others claim that medicine has changed to make it a non-issue. On the more "modern" branches of Orthodox Judaism, there are many who are willing to say that the rabbis at that time were wrong in their science.

However, no one that I have ever heard of follows this ruling today. We break Shabbat to save any baby's life.

So the school that you teach at may be very right-wing and thus teaches that the rabbis of the Talmud were correct and that nature has not changed. I personally cannot begin to understand or explain why, but you might want to ask the head of Judaics.

For more context, vague dates on the above sources are:

  • Tosefta (part of the oral law): c. 200
  • Talmud (commentary on the oral law): c. 500
  • Shulchan Aruch (legal code): mid-1500s
  • Chazon Ish (commentary on Shulchan Aruch): mid-1900s
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    It could also be the school didn't explain any further than the text because they aren't a medical school so they didn't want to spend much time on it.
    – Double AA
    Mar 6, 2013 at 5:00
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    Neither my fellow teacher nor I want to imply that any of the rabbis are wrong. I'm fine with letting the girls make up their own mind about that, and I have no room to comment since I have never in my life studied the things that they are studying. Besides, I don't personally view it that the rabbis were wrong, just maybe misinformed, and we discuss that society and technology as we know it have changed significantly over the years. From a scientific and non-religious standpoint, I think my coworker and I would be safest to simply leave it at "Technology has changed" perspective
    – Meg Coates
    Mar 6, 2013 at 14:45
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    and leave all commentary on rabbinical discourse to the Judaics teachers :-D
    – Meg Coates
    Mar 6, 2013 at 14:47

First, you should remember how bad infant mortality was in those days. So what it says about how some infants were considered not viable (and thus could not be touched on Shabbos), no longer applies today when infant mortality is much lower. You should talk about the change in infant mortality with your students.

The way you phrased your question implies that the girls believe that "if only the baby had been born a little earlier it would have been stronger". This is NOT what the Talmud says.

The Talmud says that there are babies with 7 month gestation, and some with 9.

But a baby does not go from strong-weak-strong. A 9 month baby gets stronger each month including the 8th, for a 9 month baby being born in the 7th month would be very bad.

Today we no longer see any 7 month babies. All the babies are 9 month babies.

From Rambam, Shabbos, Chapter 25, a footnote by R' Eliyahu Touger:

Yevamot 80b states that a child born after only eight months will surely die. Therefore, even while he is still living, it is forbidden to carry him on the Sabbath.

Tosafot, Shabbat 135a, states that this ruling is no longer followed, since at present it is impossible to determine exactly when a child was conceived. Therefore, we cannot be certain of the length of time the mother was pregnant. Furthermore, the advances in medical technology have enabled us to save the lives of many babies who would surely not have survived in previous generations. At present, it is a mitzvah to attempt to save the lives of all premature babies, even if doing so involves performing a forbidden labor on the Sabbath.

From Rambam, Milah, Chapter 1, and the footnote is by R' Eliyahu Touger:

Halacha 13

[The following principles apply when] a child is born in the eighth month [of pregnancy]:1 If the child's nails and hair are completely formed, we assume that this is a completely formed infant that should have been born in the seventh month, but whose birth was delayed. Hence, the baby may be carried on the Sabbath, is not considered to be a stone, and may be circumcised on the Sabbath.

If, however, when the baby was born, its hair and nails were incompletely formed, we can be certain that this child is in its eighth month of development and should not have been born until the ninth month, but was born prematurely. Therefore, he is considered as a stone and may not be moved on the Sabbath.

Nevertheless, if such an infant remains alive for thirty days, he is considered to be a child who will live and is governed by all the same rules as other infants.2 Whenever a human child lives longer than thirty days, it is no longer considered to be a stillborn.

Halacha 14

[The following rules apply when] a child is born in the seventh month of gestation: If a child is born with his limbs completely formed,3 we assume that he will live and he should be circumcised on the eighth day [even if it falls on the Sabbath].

If there is a question whether a child4 was born in the seventh month or in the eighth month, he can be circumcised on the Sabbath. The rationale is: If he was born in the seventh month and his limbs are completely formed, it is appropriate that [his circumcision] supersede [the prohibitions against labor on] the Sabbath. If he was born in the eighth month, circumcising him [does not constitute a violation of the Sabbath prohibitions].5 It is like cutting meat, because he is like a stillborn if he is, in fact, born in the eighth month.

Footnote 1: (the rest don't discuss this topic):

The comprehension of this and the following halachah are dependent on the following two Talmudic passages:

[The prohibitions against labor on] the Sabbath are superseded for [the circumcision of a child] born in the seventh month, but not for a child born in the eighth month (Shabbat 135a).

A child born in the eighth month is like a stone and may not be carried [on the Sabbath]. His mother may, however, lean over him and nurse him.... Rabbi states: [This is when] his physical features reflect his [lack of development]; i.e., when his hair and nails are not completely formed. [Rabbi's statements imply that] if [his hair and nails] are completely formed, he is a baby that should have been born in the seventh month, but whose birth was delayed (Yevamot 80b).

From these passages, it appears that the Sages considered that there were two periods of gestation that could produce healthy babies, a seven-month period and a nine-month period. Therefore, a baby who was born in the seventh month was considered to be healthy, and circumcision could be performed on the Sabbath.

In contrast, a baby born in the eighth month was generally considered to be unhealthy. Not only was the baby not to be circumcised on the Sabbath, but moving it at all was forbidden. Since it was likely to die, it was considered to be muktzeh. If, however, a baby born in the eighth month looks healthy, we assume that it should have been born in the seventh month, but its birth was delayed. Therefore, it is considered a healthy baby and it may be circumcised on the Sabbath.

We have used the past tense in the above explanation, because these laws are no longer practiced, and all babies are allowed to be moved on the Sabbath. Tosafot, Shabbat, loc. cit., state that at present, it is no longer possible to determine exactly when a child was conceived, and we therefore do not know the month of pregnancy the mother was in. Furthermore, the advances in medical technology have enabled the lives of many premature babies to be saved despite the fact that, without these new developments, these babies would surely not have survived. At present, it is considered a mitzvah to try to save the lives of any premature babies, even if doing so involves carrying out forbidden labors on the Sabbath.

Also, it must be emphasized that, as stated in Halachot 16-18, a child is circumcised only when it is healthy and there is no danger involved. This is surely relevant with regard to premature infants. Rarely, if ever, would a doctor grant permission for such a baby to be circumcised on the eighth day of his life.

(I hope I didn't overdo it with copying the text.)

  • 1
    Did we ever see 7-month babies? Also Tosfot's suggestion would not seem to apply nowadays.
    – Double AA
    Mar 6, 2013 at 5:23
  • I hadn't even considered the infant mortality standpoint!
    – Meg Coates
    Mar 6, 2013 at 14:36

RaMBaM, Rabbi Mosha ban Maimon, Maimonides, was the biggest doctor in his time in Egypt working under the sultan Saladin (I think). He was not only a great scientist but was also a known philosopher and one of the biggest rabbis in his time period, and his teachings are still held high by most if the Jewish world. In his book, Morah HaNavuchim, Guide for the Perplexed, he describes that the sciences in the time of the sages were not as they were in his times, and that we can't blame the sages for their teachings because it was the science in their times which was wrong not the sages themselves. Well, the same rule, given by Maimonides, applies to him too, for the science in his time is not like our science and he should not be blamed for it; but it should be understood that they did the best they could in this field without using any of the super high tech stuff we have nowadays. So my approach to this problem of yours would be that you should quote Maimonides and explain to your students who he was, and explain what he said regarding science, and explain to them that a person is not infallible and should not be mad that science nowadays states something different from what's in a book which contains knowledge from over 2000 years ago. The Talmud is not a science book but a book of laws. They should learn the laws and study science from a science text book. Something along those lines would do good I hope. HasSlocho Rabo (much success) and I hope the kids don't take this a whole different way than expected.

  • When I wake up, I can probably add sources with quotes if necessary. Mar 6, 2013 at 6:12
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    If I may, I suggest that if you wish to follow this advice, it should not be you saying this. Ask one of the Judaic teachers or staff instead. (Also this does not come from Maimonides. He is quoting the Talmud, this answer should be edited to clarify that.)
    – Ariel
    Mar 6, 2013 at 6:24
  • If I recall he only writes this in regard to Astronomy.
    – mevaqesh
    Feb 23, 2015 at 17:43
  • @mevaqesh rambom zl believed the sages were wrong in scientific aspects, however in his time many were still believed in. Such as animals coming from the ground spontaneously Feb 23, 2015 at 19:35
  • Again please cite the sources so we can clarify Rambam's intent.
    – mevaqesh
    Feb 27, 2015 at 5:55

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