The fundamental theory of genetics states that genes—chains of nucleotides in our DNA that are at the core of the characteristics of every living organism—act in pairs. One gene is described as dominant, and the other is viewed as recessive.
For example, in humans one pair of genes defines the individual’s eye-color: brown or blue. In this pair, the brown gene is considered dominant, and the blue is recessive. What this means is that the individual receives one half of his DNA from his father and the other half from his mother. If one of these halves contains the gene that codes for brown eyes, even if the other contains the gene for blue eyes, the child’s eye color (the phenotype) will be brown. Only if both sets of DNA from both parents contain the gene that codes for blue eyes, will the child sport blue eyes.
Interestingly, this model allows us to describe gender as another characteristic of the body that is determined by a pair of genes, one coding for male, the other for female. These genes are located on chromosomes, which are long strands of DNA material that can contain hundreds and thousands of genes. The two chromosomes that code for male and female genders are known as Y—the male chromosome—and X—the female chromosome. These names actually describe the physical shape of the two chromosomes. To code for a male phenotype, the child’s DNA must have YX chromosomes. To code for a female the child’s DNA must have XX chromosomes. Thus, the Y chromosome, which when present dictates that the child will be male, is relatively dominant to the X chromosome. This reflects the sages’ statement (associated with an explanation of the verse, “Be fruitful and multiply, fill the earth, and conquer it”) that, “it is the nature of the male to conquer; it is not the nature of the female to conquer.”
However, it seems that the contribution to the child’s gender phenotype is not equally weighted between the father and the mother. The mother, who has XX, can only contribute an X chromosome, thus only the father can contribute a Y chromosome (from his YX configuration) and it is the father alone that “determines” the child’s gender. Yet, the Torah seems to state that the mother too plays a role in determining the child’s gender, as we see in the verse, “A woman when she produces seed and gives birth to a male.”
The way to reconcile the two views regarding the woman’s contribution to her offspring’s gender is by recognizing that the genetic model treats the recessive gene (and by extension, the chromosome) as non-contributing and non-active in the individual organism. The reason it is carried by an individual is to allow its transmission to future generations of the species. Case in point, the X chromosome in the male is recessive since the male’s phenotype does not rely on the X chromosome—the male’s female chromosome—specifically it does not rely on the gender determining genes on the X chromosome. Similarly, in a woman, the second X chromosome is deemed recessive as far as determining her gender.
But according to Torah, everything has value, even here and now (not just in the future). In fact, it is specifically those things that seem recessive or inactive (rendering them passive) that constitute the secret of success. This is also the secret of the Jewish people, as alluded to in the sages’ statement that our calendar is based on the moon (whose light is passive, since it originates in the sun), while the nations base their calendar on the sun which is dominant. We must conclude then that the recessive X chromosome is not meaningless in either the male or the female. In the male, it functions as a concealed “feminine” attribute, while in the female, it acts as a concealed “male” attribute!
To illustrate the contribution of the recessive X chromosome, we can recount a story told about the Rebbe of Kotzk. One of his chasidim came to him and complained that even though the Torah states that “he [the man] will rule over you [the woman],” in his house, the situation is reversed and his wife rules over him. The Kotzker replied that the Torah’s statement is indeed eternal, but the full phrase reads, “your [the wife’s] urge shall be for your husband, and he will rule over you”—if the wife is the one yearning for her husband, then he will rule over her, but if it is you that yearn for your wife, the rebbe concluded, the situation is reversed.
On our verse, the sages state,
Rabbi Yitzchak says in the name of Rabbi Ami: If the woman emits seed first, she gives birth to a male, and if the man emits seed first, she gives birth to a female, as it is stated: “A woman when she produces seed and gives birth to a male.”
The “woman” and the “man” in this passage can be interpreted metaphorically. Whomever is attracted first, in what is known as “an awakening from below” to connect with the other is referred to as the “woman.” Thus, if it is the husband that is drawn to his wife, he awakens his “woman,” i.e., his recessive X chromosome and therefore a girl will be born. But if it is the wife who is attracted to her husband, it is her “woman” that awakens, i.e., her recessive X chromosome, which then draws to it, spiritually, a sperm with the dominant Y chromosome and the child will be a boy.
(from Torah Chaim)
