Navigating Niddah: The Science Behind the Sugya

By: Temmi Lattin  |  December 18, 2019

By Temmi Lattin

I decided to start learning Daf Yomi this year. One of the most exciting parts about embarking on this 7.5-year learning adventure and process was the deal I made with my parents: they will pay for every Masechet that I complete. The image of a full set of Shas with each Masechet learned and annotated still motivates me to continue learning three months later. With the image of my future set of Shas in mind, I have been learning from a large, traditional Vilna Shas. During these past months, I’ve carried my big Masechet Niddah all over New York City and beyond; a big portion of my learning takes place on the subway. I’m a lot more successful in my learning when it’s not rush hour, because my Gemara’s conspicuous size takes up two seats, and when I sit down to learn such a huge sefer, in a language that most of the passengers around me probably don’t recognize, I inevitably get some comments. Usually people will briefly comment “yasher koach” or “good for you,” but sometimes I’ll have memorable conversations with people on the subway, who ask me for advice about starting to learn Gemara (don’t be scared, just start with any and all the resources you can find), or ask me about my background and what inspired me to start learning. Realizing that my learning has inspired people on the subway to start learning, keeps me motivated.

Other than facilitating great conversations and positive interactions, my Gemara’s size means that I have space on the sides of the pages to jot down my notes and thoughts, often about the scientific aspect of the Gemara’s statements. On daf 19a, the Gemara begins with a Mishna about the five different colors of blood that make a women tameh (impure), which according to the Tana Kamma are: red, black, the bright part of a crocus flower, the color of water that floods red earth, and the color of diluted wine. Many other opinions are quoted, with other colors and shades deemed pure or impure. As I learn, I often wonder if the cases brought by the Gemara are scientifically plausible. For example, the Gemara asks a question about the status of green blood. While this seems like a hypothetical and impossible situation, there is actually a rare blood condition called sulfhemoglobinemia, caused by high sulfur exposure, that can give someone’s blood a green tint. 

In this case, the Gemara can align with the current scientific knowledge, but it does not always work out this way. On 19b, the Gemara goes back to the color red that was mentioned in the Mishna with the other four colors, and tries to clarify what shade of red the Mishna is referring to. Although the Mishna explicitly states that this is the same color as blood from a wound, the Gemara explains what kind of wound is being referred to. Rabbi Abahu suggests the Mishna is referring to one very specific case: this red is the color of blood that flows from the smallest finger of the hand a young man, under the age of twenty, who has not been married to a woman, after it has been wounded, healed, and wounded again. The Gemara seems to suggest that the color and characteristics of blood change with age and personal circumstances. The concept of the blood of younger people being characteristically different from older people is something that is still currently being explored. The FDA addressed this question by issuing warnings this year about the practice of rejuvenating older people with blood transfusions from younger donors. But, the FDA stated that this practice is not scientifically founded. 

There are many Halachic sources which explore the tension of grappling with overt scientific inaccuracies in the Gemara. However, these disparities don’t negate the fact that the Gemara is the source for the Halachot that we follow, and is full of teachings and stories that impart meaningful lessons such as that on daf 31a. 

The daf begins with with the well-known concept of the three partners involved in creating a child: the mother, father, and Hashem. This is followed by a statement of Rav Pappa, who illustrates Hashem’s role in childbirth by comparing the limited and finite nature of human beings with the infinite and unlimited nature of Hashem. His first comparison is to humans who can put an object in a flask that is tied shut with its opening facing upward, but still cannot be absolutely certain that the object inside won’t fall out. In contrast, when Hashem puts a fetus inside a woman’s womb, it’s upside down with the opening downward, yet the fetus stays inside. I personally am struck with amazement that the baby stays upside down in the womb for nine months and that it’s only when the baby is fully developed (assuming the pregnancy goes smoothly), that labour begins. Even now, centuries later, scientists still aren’t sure about what exactly triggers the transition from the body actively working to sustain the pregnancy and keep the baby inside the womb, to the processes of labor and delivery. While there are serious theories about the nature of the stimulus, including hormonal signals or planetal changes, and while it’s clear that the process is multifactorial, there is still present in the scientific community today a sense of awe toward this miraculous transformation.

In a similar vein, Rabbi Yosef HaGlili brings up a different point of contrast between finite beings and an infinite G-d. When people plant seeds of different types together, each seed grows according to its distinct species. On the other hand, when Hashem forms the fetus in a woman’s womb, it’s made from the distinct seeds of both the father and the mother, yet the offspring is only one sex, either the father’s or the mother’s. To illustrate, he compares a dyer who combines different colored herbs in a pot to produce a single colored dye, to Hashem, who makes a fetus from a combination of the man and woman, with each parent contributing distinct elements. 

Earlier in the sugya, the Gemara explains that the father’s seed contributes specific characteristics, such as the white of the eye, and the mother’s seed contributes other characteristics, like the black of the eye. Ignoring the question about what the woman’s seed is, we know that a child has 46 chromosomes, 23 of which are from the father and 23 of which are from the mother. The Gemara is correct in stating that each parent contributes separate, distinct traits to their offspring. The Gemara, predating Mendelian genetics, hints to these genetic concepts. Although it doesn’t get them totally correct, the lesson about the wondrousness of genetic inheritance and Hashem’s blueprint of human creation remains, and is bolstered with, our continued knowledge of genetics.

Amongst the backdrop of twenty-first century scientific knowledge, many of the statements in the Gemara are obviously inaccurate. When the Gemara’s words don’t align with science, I view it as an opportunity to experience the progression of scientific knowledge before our eyes. On daf 31a, the Gemara provides clear instructions as to how to conceive a baby boy or a baby girl. While reconciling the dichotomy of the Gemara’s scientifically inaccurate statements and contemporary scientific consensus is often not easy, I find that this pushes the reader to look beyond the science, to find the inner message that’s being imparted. While I don’t always have the answers and can’t explain the errors, these inaccuracies lead us to celebrate the times when the Gemara does get the science right, or when seemingly false statements can be explained with current scientific understanding. 

Masechet Niddah is a symbolic pillar of faith. It epitomizes that at the end of the day, regardless of the fact that not everything written in the Torah parallels our worldview, it is still a Torat Chayim (living Torah), and its laws will always be followed and cherished.