Ay'lonit

In Jewish tradition, the term ay'lonit (איילונית in Hebrew, translation "ram-like woman") refers to a person born female at birth who later developed "male characteristics". During puberty, an ay'lonit will not develop secondary-sex characteristics and is assumed to be infertile. The secondary-sex characteristics are referred to as "male" characteristics in the Talmud. "Male characteristics" can include a deeper voice, painful intercourse, small breasts, a lack of pubic hair, a period, and a normal libido

In traditional Judaism, gender plays a central role in legal obligations (see also mitzvah). Thus, the gender identities of the Talmud (see also androgynos, tumtum, and saris) were created for the purpose of fitting into their legal system. While considered gender-identities, they should not be read under a modern definition.

Biological basis
The ay'lonit is not simply infertile. Based on the "male characteristics" described in the Talmud, the ay'lonit's condition is most similar to Turner syndrome:
 * A genetic abnormality in which a woman is partially or entirely missing one of their X chromosomes
 * Occurs in 1 out of 2,000-4,000 female births (only found in females)
 * Symptoms include: Infertility problems, webbed neck, short stature, metabolic issues, and delayed/absent sexual developments

References in holy texts
There are about 80 references in the Mishnah and Talmud and 40 in classical Midrash and Jewish law codes.

Examples
"A woman who is twenty years old and has not grown two pubic hairs..is classified as an Aylonit..." (Niddah, Chapter 5, 47b)

"These are the signs that a woman is an Aylonit: She has not developed breasts, she has difficulty during sexual intercourse [that is, she has a diminished libido], the mons pubis is lacking, and she has such a deep voice that it is indistinguishable from that of a man..." (Mishneh Torah, Hil. Ishus, 2:6)

"Rav Naḥman said that Rabba bar Avuh said: Our mother Sarah was initially a sexually underdeveloped woman [ay'lonit], as it is stated: “And Sarah was barren; she had no child” (Genesis 11:30). The superfluous words: “She had no child,” indicate that she did not have even a place, i.e., a womb, for a child." (Yevamot 64b:2)

Distinction from saris
As stated above, ay'lonit specifically refers to a person born female who later develops "male characteristics". Saris is a person who is male at birth and later developed "female characteristics". This can occur naturally (called saris hamah) or through medical interventions (called saris adam). Though an ay'lonit can be adam (such as through the removal of their uterus or ovaries), it is more common for them to be hamah.

Ay'lonit and saris also differ in their abilities to get married. While an ay'lonit can be married, a saris has varying options. If he is saris hamah, he can get married with no restrictions because he was born that way. If he is saris adam, he cannot marry a Jewish woman because he cannot have children and this could lead her to adultery. Additionally, if a saris adam was already married, he is required to divorce his wife.

Levirate marriage
A levirate marriage requires a man to marry his late brother's widow if the couple did not have any children.


 * The Discourse: “My late brother’s wife is ay’lonit. Do I have to perform a levirate marriage?”
 * “She neither performs halitzah nor does she enter into levirate marriage, as the mitzvah of levirate marriage applies only to a woman capable of conceiving a child.”
 * "If the lower sign [of two hairs] appears before the upper sign [of the breasts] does, she can participate in halitzah or yibbum. If the upper sign appears before the lower sign does, even though this is impossible, Rabbi Meir says: she does not participate in halitzah or yibbum. And the Sages say: she must participate in either halitzah or yibbum. For they have said: it is possible for the lower sign to appear before the upper sign has, but it is impossible for the upper sign to appear before the lower sign has."