Our Gemara on Amud Aleph describes how a cattle raiser could influence the production of a red heifer by placing a red cup in front of it during conception. The Gemara challenges the efficacy of this technique—after all, if it really worked, red heifers wouldn’t be so rare. It concludes that this method might work, but only with breeds that already tend toward producing red heifers.
This Gemara is an illustration of the ancient medical and biological belief that a fetus is influenced by what the mother experiences—emotionally, visually, or physically—during conception and gestation. One of the strongest expressions of this belief can be found in the Iggeres HaKodesh (Part 4), attributed to the Ramban. He maintains that if a man has holy intent and cultivates love in his wife during intimacy, her thoughts will then align with his via the love and attachment, and the resulting child will be conceived in a holy atmosphere. Ramban supports this by referencing both the medical beliefs of his era and Yaakov’s behavior in Bereishis (30:37), where he seems to employ a similar technique to influence the outcome of his sheep’s offspring.
Some might dismiss such ancient beliefs as primitive superstition. However, that dismissal is simplistic and arrogant. The ancients, lacking precise empirical tools, often perceived patterns and truths that modern science has only recently begun to verify. For instance, it is clearly observable that German Jews often resemble Germans, Syrian Jews resemble Arabs, and Polish Jews resemble Eastern Europeans. While genetics offers one explanation, there’s growing evidence that environmental influences—including stress—can shape gene expression. This is the field of epigenetics, and even more recently, psychological epigenetics.
For example, Rachel Yehuda’s 2015 study in Biological Psychiatry examined Holocaust survivors and their children. The study found epigenetic changes in cortisol regulation—specifically in the FKBP5 and NR3C1 genes. In plain terms: Holocaust survivors with PTSD had low cortisol levels, impairing their ability to regulate stress. Their children—especially those whose mothers had PTSD—also exhibited altered stress responses, likely due to epigenetic modifications passed on during gestation.
Even without such scientific confirmation, the ancients intuitively understood that beliefs, trauma, and emotional states could be passed down across generations. They didn’t have language like “maternal attachment theory,” but they expressed it through spiritual metaphors. Their “spiritual” language is akin to modern physics using math to describe invisible forces—the metaphors are different, but the truths are parallel.
In an earlier post, I discussed how misdirected sexual impulses are said to generate demons. These aren’t cartoonish figures with pitchforks, but rather dangerous inner forces. The Zohar (I:55a) says that Adam, after his sin, separated from Chava for 130 years and, during that time, begat spirits and demons. The Rambam (Guide I:7) explains that these offspring weren’t truly human—they had human form but lacked the essence of humanity: moral purpose and Divine likeness.
Such a being—endowed with intelligence and free will but misusing it—produces destructive forces. The sons of Adam before Seth were not fully human, and thus the Torah says only of Seth, “he begat a son in his likeness and form.” According to Rambam, “demon” here is a metaphor for a human who lives as a distortion of their potential. The Nazis and Hamas are not just evil—they are, in this sense, demons: beings with intellect and choice, yet perverted to monstrous ends.
Our thoughts and emotional environments affect what we produce—whether families or ideologies. This is not superstition; it is deep psychological truth, whether explained through mystical tradition or scientific theory.