Kiddushin 16b ~ Measuring Puberty

קידושין טז, ב

בן תשע שנים שהביא שתי שערות שומא מבן ט' שנים ויום אחד עד בן י"ב שנה ויום אחד ועודן בו שומא ר' יוסי בר' יהודה אומר סימן בן י"ג שנה ויום אחד דברי הכל סימן 

If a nine year old grows two hairs [in the pubic region] the growth should be attributed to a mole [and not as a sign of sexual maturity]. [If these hairs grow] from the age of nine years and one day until twelve years and one day, and they are still there [when the child reaches twelve, one opinion is that they should be attributed to a] mole, and Rabbi Yossi bar Rabbi Yehuda says they are a sign of sexual maturity. [If these hairs grow] when the child is thirteen years old and one day, then everyone agrees they are a sign of sexual maturity...(Kiddushin 16b)

Pre-Modern Descriptions of Puberty

The way in which children develop into adults has fascinated us for centuries.  In fact, the earliest surviving statement on human growth dates back to the sixth century BCE, (not long after the prophet Jeremiah lived) and is by the Athenian poet Solon. One critic described his poem as combining "scientific sense with philosophical probability (if not, regrettably, with poetic elegance)." Here is Solon:

A young boy acquires his first ring of teeth as an infant and sheds them before he reaches the age of seven years. When the god brings to an end the next seven year period, the boy shows the signs of beginning puberty. In the third hebdomad, [ a period of seven years] the body enlarges, the chin becomes bearded and the bloom of the boy's complexion is lost. In the forth hebdomad physical strength is at its peak and is regarded as the criterion of manliness; in the fifth hebdomad a man should take thought of marriage and seek sons to succeed him. In the sixth hebdomad a man's mind is in all things disciplined by experience and he no longer feels the impulse to uncontrolled behavior. In the seventh he is at his prime in mind and tongue and also in the eighth, the two together making fourteen years. In the ninth hebdomad, though he still retains some strength, he is too feeble in mind and speech for the greatest excellence. If a man continues to the end of the tenth hebdomad, he has not encountered death before due time.

Hippocrates believed that puberty could be delayed in areas where "the wind is cold and the water is hard". Rabbi Shimon ben Gamliel (d. 70CE) would have agreed, because he thought that the growth of pubic hair was hastened in those who used the bathhouse regularly.  But it is especially interesting to compare Aristotle's writings on puberty with those of the Talmud (which of course were codified several hundred years later).

In man, maturity is indicated by a change in the tone of the voice, by an increase in size and an alteration in appearance of the sexual organs, and also by an increase in size and alteration in appearance of breasts, and above in the hair growth above the pubes.

Aristotle (d. 322 BCE) seems to have put a lot of weight on the growth of pubic hair, just like the rabbis of  in the Talmud did many years later. Galen, who died in 199 CE, was cautious about timing the onset of puberty: "Some begin puberty at once on the completion of the fourteenth year, but some begin a year or more after that" (De Sanitate Tuenda, or p288 of this translation). Jumping forward several centuries, we find that girls in Tuscany in 1428 were allowed to marry aged eleven and a half, although they were forbidden to live with their husbands until they were twelve. However the Bishop of Florence (later canonized as Saint Anthony) declared that cohabitation was allowed "provided the girl had reached puberty." 

The Tanner Scale

Today, the stage of sexual maturity in children is most commonly measured using the Tanner scale, described by the British pediatrician James Tanner, who died in 2010.  (He wrote a fascinating History of the Study of Human Growth as a sort of a hobby, but his day job was working as a Professor at the Institute of Child  Health in London.)  Here is how Tanner described his scale in boys, (from his original paper published in 1970):

Stage 1: Pre-adolescent. The velus [sic] over the pubes is no further developed than that over the abdominal wall, i.e. no pubic hair.

Stage 2: Sparse growth of long, slightly pigmented downy hair, straight or slightly curled, appearing chiefly at the base of the penis. This stage is difficult to see on photographs, particularly of fair-headed subjects...

Stage 3: Considerably darker, coarser, and more curled. The hair spreads sparsely over the junction of the pubes. This and subsequent stages were clearly recognizable on the photographs.

Stage 4: Hair is now adult in type, but the area covered by it is still considerably smaller than in most adults. There is no spread to the medial surface of the thighs.

Stage 5: Adult in quantity and type, distributed as an inverse triangle of the classically feminine pattern. Spread to the medial surface of the thighs but not up the linea alba or elsewhere above the base of the inverse triangle.

“There has been less discussion in the literature as to whether the appearance of pubic hair has advanced in females, although this does seem to be the case, pubarche having advanced by at least 6 months. The PROS study found stage II pubic hair to be apparent in African-American females at a mean age of 8·78 years and 10·51 years in whites.”

— Slyper, AH.The pubertal timing controversy in the USA, and a review of possible causative factors for the advance in timing of onset of puberty. Clinical Endocrinology (2006) 65, 1–8

Tanner also described other signs of sexual maturity, since growth of pubic hair is not the only maker.  In boys, for example, Tanner used a five-stage system for genital growth: in stage one, the  "testes, scrotum, and penis are of about the same size and proportion as in early childhood," whereas in stage two, "the scrotum and testes have enlarged and there is a change in the texture of the scrotal skin..."  Tanner noted that the stages of pubic hair development and the stages of genital development differ, so that a boy may reach full genital maturation sooner than he reaches stage five on the pubic hair scale.  

From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45: 13-25.

Tanner's work reveals what we already know intuitively. Maturity, whether sexual or emotional, is a process that takes time and proceeds through many stages. The rabbis of the Talmud relied predominantly on one marker of adulthood:  sexual maturity as evidenced by a minimal of pubic hair growth.  But they used it in conjunction with the age of the child.  They also understood that the onset of these signs might be sooner in some children and later in others.

Sequence of events in puberty in girls (top) and boys. From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45:22.

In most European countries, the age of the onset of puberty (as measured by the onset of menstruation) has fallen by about a year per century. Boys also seem to be developing earlier than previously, possibly by more than a year. Data from the US National Health and Nutrition Examination Survey (NHANES III) study of boys aged 8 –19 years, suggests that the mean age of onset of male genital development based on visual inspection is now about nine years for African-Americans and ten years for white boys.

Another First?

Last year we analyzed talmudic statements of R. Hiyya (who lived in the second half of the second century,) and Rava, (d. 350CE) who appear to have been the first to report an association between obesity and delayed puberty in boys.  They claimed that puberty may be delayed in boys who are underweight, and this association has now been confirmed. As we noted then, none of the researchers has credited these talmudic sages for being the first to notice these associations. But Rava and R. Hiyya were first, and firsts count for something in science. The Baraita in today's daf  may be the first recorded discussion of the lower limits of sexual maturity. But the rabbis of the Talmud used other markers of maturity, like breast development which is discussed in Masechet Niddah (47a).They distinguished between "lower" and "upper" signs of puberty, and so presaged the work of Tanner. (The rabbis also ruled that "all girls who are examined are examined by women". Thank heavens.)

There were several reasons why the Talmud had to codify the stages of physical maturity.  Among these were to allow a father to decide to whom his daughter would marry.

A father who declares...my daughter is twelve years and a day is believed in order to marry the child off...(רמב׳ם הל׳ אישות ב:כג)

Today, any notion that a child under the age of twelve (or sixteen for that matter) would be mature enough to marry is utterly repugnant to us. But according to the UN in developing countries, one in every three girls is married before reaching the age of eighteen, and one in nine is married by the age of fifteen.  When we read the Talmud we often get a glimpse into a Jewish world very different from our own. But some practices of that world still exist outside of the Jewish community today, to the shame of us all. 

From United Nations Children’s Fund, Ending Child Marriage: Progress and prospects, UNICEF, New York, 2014.

Niddah 47a ~ Measuring Puberty in Girls, Boys, and the Underprivileged

We are in the middle of a long discussion about signs of puberty in girls. Yesterday we read a Mishnah that described the developing breasts of a young girl, and when they may indicate legal adulthood:

נדה מז,א

סימנין ר' יוסי הגלילי אומר משיעלה הקמט תחת הדד ר"ע אומר משיטו הדדים בן עזאי אומר משישחיר הפיטומת רבי יוסי אומר כדי שיהא נותן ידו על העוקץ והוא שוקע ושוהא לחזור

What are the signs that indicate grown womanhood? Rabbi Yosei HaGelili says: Grown womanhood begins from when her breast grows sufficiently so that a fold appears below the breast. Rabbi Akiva says: It begins from when the breasts sag onto the chest. Ben Azzai says: It begins from when the areola at the tip of the breast darkens. Rabbi Yosei says: It begins when the breasts have developed to a size where a person places his hand on the nipple and it depresses and it is slow to return.

The Talmud further debates these various stages of development, and cites Shmuel, the Babylonian physician who died in 254 CE.

אמר שמואל לא משיעלה הקמט ממש אלא כדי שתחזיר ידיה לאחוריה ונראית כמי שיעלה הקמט תחת הדד

Shmuel says: This does not literally mean from when her breast grows sufficiently so that a permanent fold appears below the breast. Rather, it means that the breast has grown enough so that if she were to stretch her hand behind herback, it would appear as though her breast has grown sufficiently that there is a fold below the breast.

It was necessary to have a similar measure of puberty in boys, as they matured into legal adults (and which today would predominantly mean that they are now capable of accepting their bar mitzvah gifts). Here is the discussion in another tractate, Kiddushin (from where some of this post was originally published.)

קידושין טז, ב

בן תשע שנים שהביא שתי שערות שומא מבן ט' שנים ויום אחד עד בן י"ב שנה ויום אחד ועודן בו שומא ר' יוסי בר' יהודה אומר סימן בן י"ג שנה ויום אחד דברי הכל סימן 

If a nine year old grows two hairs [in the pubic region] the growth should be attributed to a mole [and not as a sign of sexual maturity]. [If these hairs grow] from the age of nine years and one day until twelve years and one day, and they are still there [when the child reaches twelve, one opinion is that they should be attributed to a] mole, and Rabbi Yossi bar Rabbi Yehuda says they are a sign of sexual maturity. [If these hairs grow] when the child is thirteen years old and one day, then everyone agrees they are a sign of sexual maturity...(Kiddushin 16b)

This interest in the sexual development of children might be unseemly, but it had a very legitimate purpose. Certain legal rights are given to a woman once she reaches puberty and leaves the legal status of a child. It was therefore necessary to identify when, exactly a girl enters legal adulthood. Hence the talmudic discussion.

In a related vein, pediatricians and endocrinologists need to understand the natural process of puberty in order to identify a medical problem that needs treating. They too developed measures of sexual maturity, as we will see below.

Pre-Modern Descriptions of Puberty

The way in which children develop into adults has fascinated us for centuries.  In fact, the earliest surviving statement on human growth dates back to the sixth century BCE, (not long after the prophet Jeremiah lived) and is by the Athenian poet Solon. One critic described his poem as combining "scientific sense with philosophical probability (if not, regrettably, with poetic elegance)." Here is Solon:

A young boy acquires his first ring of teeth as an infant and sheds them before he reaches the age of seven years. When the god brings to an end the next seven year period, the boy shows the signs of beginning puberty. In the third hebdomad, [ a period of seven years] the body enlarges, the chin becomes bearded and the bloom of the boy's complexion is lost. In the forth hebdomad physical strength is at its peak and is regarded as the criterion of manliness; in the fifth hebdomad a man should take thought of marriage and seek sons to succeed him. In the sixth hebdomad a man's mind is in all things disciplined by experience and he no longer feels the impulse to uncontrolled behavior. In the seventh he is at his prime in mind and tongue and also in the eighth, the two together making fourteen years. In the ninth hebdomad, though he still retains some strength, he is too feeble in mind and speech for the greatest excellence. If a man continues to the end of the tenth hebdomad, he has not encountered death before due time.

Hippocrates believed that puberty could be delayed in areas where "the wind is cold and the water is hard". Rabbi Shimon ben Gamliel (d. 70 CE) would have agreed, because he thought that the growth of pubic hair was hastened in those who used the bathhouse regularly.  But it is especially interesting to compare Aristotle's writings on puberty with those of the Talmud (which of course were codified several hundred years later).

In man, maturity is indicated by a change in the tone of the voice, by an increase in size and an alteration in appearance of the sexual organs, and also by an increase in size and alteration in appearance of breasts, and above in the hair growth above the pubes.

Aristotle (d. 322 BCE) seems to have put a lot of weight on the growth of pubic hair, just like the rabbis in the Talmud many years later. Galen, who died in 199 CE, was cautious about timing the onset of puberty: "Some begin puberty at once on the completion of the fourteenth year, but some begin a year or more after that" (De Sanitate Tuenda, or p288 of this translation). Jumping forward several centuries, we find that girls in Tuscany in 1428 were allowed to marry aged eleven and a half, although they were forbidden to live with their husbands until they were twelve. However the Bishop of Florence (later canonized as Saint Anthony) declared that cohabitation was allowed "provided the girl had reached puberty." 

According to Celia Roberts from Lancaster University in the UK, the first textbook on growth, written in 1729 by Prussian physician Johann Stoller, was entirely theoretical and contained no actual measurements of children. They were not measured until 1754, when the physician Christian Jampert presented a thesis based on measurements of children in a Berlin orphanage. Roberts continues:

In 1777 the first longitudinal study of growth was reported in George LeClerc Comte de Buffon’s Natural History. Based on measurement of his assistant Phillip Gueneau de Montbeillard’s son from birth to adulthood (1759–77), this study confirmed the concept of a ‘pubertal growth spurt’ and seasonal changes in growth rate. Some 60 years later Belgian mathematician Adolphe Quetelet combined a mathematical approach with empirical data on children’s growth, using data from measurements of his own children.

The Tanner Scale

Today, the stage of sexual maturity in children is most commonly measured using the Tanner scale, described by the British pediatrician James Tanner, who died in 2010.  (He wrote a fascinating History of the Study of Human Growth as a sort of a hobby, but his day job was working as a Professor at the Institute of Child  Health in London.)  Here is how Tanner described his scale in boys, (from his original paper published in 1970):

Stage 1: Pre-adolescent. The velus [sic] over the pubes is no further developed than that over the abdominal wall, i.e. no pubic hair.

Stage 2: Sparse growth of long, slightly pigmented downy hair, straight or slightly curled, appearing chiefly at the base of the penis. This stage is difficult to see on photographs, particularly of fair-headed subjects...

Stage 3: Considerably darker, coarser, and more curled. The hair spreads sparsely over the junction of the pubes.

Stage 4: Hair is now adult in type, but the area covered by it is still considerably smaller than in most adults. There is no spread to the medial surface of the thighs.

Stage 5: Adult in quantity and type, distributed as an inverse triangle of the classically feminine pattern. Spread to the medial surface of the thighs but not up the linea alba or elsewhere above the base of the inverse triangle.

Tanner also described five stages of breast development in girls, in a paper he published in 1969.

Stage 1: Pre-adolescent; elevation of papilla only.

Stage 2: Breast bud stage;elevation of breast and papilla as a small mound, enlargement of areola diameter.

Stage 3: Further enlargement of breast and areola, with no separation of their contours.

Stage 4: Projection of areola and papilla to form a secondary mound above the level of the breast.

Stage 5: Mature stage; projection of papilla only, due to recession of the areola to the general contour of the breast.

And here is the distribution of the age on reaching each of the various signs of puberty, at least as Tanner found them in his sample of 192 white British girls in the 1960s. It shows, for example, that most of the girls reached stage 5 breast growth (B5) a little after their fifteenth birthday.

Age on reaching various stages of puberty. B: Breast stage. PH: Pubic Hair stage. M: Menarche. PHV: Peak Height Velocity. The center of each symbol represents the mean, and the length is equivalent to two standard deviations on either side of the mean. From Marshall W. A. Tanner J.M. Variations in Pattern of Pubertal Changes in Girls. Archives of Diseases in Childhood 1969. 44:291-303.

“There has been less discussion in the literature as to whether the appearance of pubic hair has advanced in females, although this does seem to be the case, pubarche having advanced by at least 6 months. The PROS study found stage II pubic hair to be apparent in African-American females at a mean age of 8·78 years and 10·51 years in whites.”

— Slyper, AH.The pubertal timing controversy in the USA, and a review of possible causative factors for the advance in timing of onset of puberty. Clinical Endocrinology (2006) 65, 1–8

Tanner also described other signs of sexual maturity, since growth of pubic hair is not the only maker.  In boys for example, Tanner used a five-stage system for genital growth: in stage one, the  "testes, scrotum, and penis are of about the same size and proportion as in early childhood," whereas in stage two, "the scrotum and testes have enlarged and there is a change in the texture of the scrotal skin…"  Tanner noted that the stages of pubic hair development and the stages of genital development differ, so that a boy may reach full genital maturation sooner than he reaches stage five on the pubic hair scale.  

From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45: 13-25.

Tanner's work reveals what we already know intuitively. Maturity, whether sexual or emotional, is a process that takes time and proceeds through many stages. The rabbis of the Talmud relied predominantly on one marker of adulthood:  sexual maturity as evidenced by a minimal of pubic hair growth or growth of the breasts  But they used it in conjunction with the age of the child.  They also understood that the onset of these signs might be sooner in some children and later in others.

Sequence of events in puberty in girls (top) and boys. From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45:22.

In most European countries, the age of the onset of puberty (as measured by the onset of menstruation) has fallen by about a year per century. Boys also seem to be developing earlier than previously, possibly by more than a year. Data from the US National Health and Nutrition Examination Survey (NHANES III) study of boys aged 8 –19 years suggests that the mean age of onset of male genital development based on visual inspection is now about nine years for African-Americans and ten years for white boys.

Another First?

Two years ago we analyzed talmudic statements of R. Hiyya (who lived in the second half of the second century,) and Rava (d. 350CE) who appear to have been the first to report an association between obesity and delayed puberty in boys.  They claimed that puberty may be delayed in boys who are underweight, and this association has now been confirmed. As we noted then, none of the researchers has credited these talmudic sages for being the first to notice these associations. But Rava and R. Hiyya were first, and firsts count for something in science.

Childhood Marriage

There were several reasons why the Talmud had to codify the stages of physical maturity.  Among these were to allow a father to decide to whom his daughter would marry.

A father who declares...my daughter is twelve years and a day is believed in order to marry the child off...(רמב׳ם הל׳ אישות ב:כג)

Today, any notion that a child under the age of twelve (or sixteen for that matter) would be mature enough to marry is utterly repugnant to us. But according to the UN in developing countries, one in every three girls is married before reaching the age of eighteen, and one in nine is married by the age of fifteen.  When we read the Talmud we often get a glimpse into a Jewish world very different from our own. But some practices of that world still exist outside of the Jewish community today, to the shame of us all. 

From United Nations Children’s Fund, Ending Child Marriage: Progress and prospects, UNICEF, New York, 2014.

a final thought: the exploitation of the vulnerable for the sake of science

Although Tanner’s work was widely recognized for its importance, it had an ugly side. He began his study in 1948 at the Highfield Branch of the National Children’s Home in Harpenden, just outside of London, and it continued until 1971. It was remarkable for its attention to detail and use of modern scientific methods and approaches, but it systematically used only disadvantaged children as research subjects. None of this was illegal back then; it wasn’t even thought of as unethical. It was only with the 1964 Helsinki Declaration of the World Medical Associations that informed consent for children by their proxies became a matter of public attention. In his work on the Harpenden study, Tanner did not describe any attempt to obtain informed consent from either the children or their parents or guardians.

Celia Roberts, the academic from Lancaster University, also notes “the significance of the disadvantaged social position of these children: living in a children’s home made it difficult to resist Tanner and Whitehouse’s scientific figurations of development.” And who were the the participants in this study?

Some were parentless children who had lived in the home since they were babies. Others – in increasing numbers as the study went on – were taken into the home “as the result of family breakdown.” They were all from working-class families and all had experienced (potentially traumatic) separation from familiar carers and surroundings. Some may have experienced abuse and/or neglect…

Any difficulties the children experienced in living at the national children’s home are effaced. The participants’ atypicality is constrained to their backgrounds which might, Tanner argues, affect the timing of their development (and hence the numerical values of their growth curves) but not its overall shape.

Reading this description of Tanner’s methods reminds us of those of another physician who used the weak and disadvantaged as his scientific subjects: none other than Shmuel. Here is what he did:

נדה מז,א

שמואל בדק באמתיה ויהב לה ד' זוזי דמי בושתה שמואל לטעמיה דאמר שמואל (ויקרא כה, מו) לעולם בהם תעבודו לעבודה נתתים ולא לבושה

Shmuel examined these stages in his Canaanite maidservant, and subsequently gave her four dinars as payment for her humiliation. The Gemara notes that in this regard Shmuel conforms to his line of reasoning, as Shmuel said that the verse: “You may enslave them forever” (Leviticus 25:46) teaches: I gave them to you for the service of slaves, but not for humiliation. Consequently, if a master humiliated his Canaanite slave, he must pay him damages.

Although they were separated by thousands of miles and almost two millennia, both Dr Tanner in London and Shmuel the Physician in Babylon used the vulnerable to further science in ways that were unethical. In fact Shmuel was perhaps the more enlightened of the two: he realized that what he had done to his young slave girl was wrong, and compensated her for it. That the Talmud recorded Shmuel’s acknowledgment is a reminder that the rabbis of the Talmud did not always use their positions of authority correctly. At the same time, it is also a reminder that sometimes they realized the error of their ways, and tried to make amends.

Kiddushin 16b ~ Measuring Puberty

קידושין טז, ב

בן תשע שנים שהביא שתי שערות שומא מבן ט' שנים ויום אחד עד בן י"ב שנה ויום אחד ועודן בו שומא ר' יוסי בר' יהודה אומר סימן בן י"ג שנה ויום אחד דברי הכל סימן 

If a nine year old grows two hairs [in the pubic region] the growth should be attributed to a mole [and not as a sign of sexual maturity]. [If these hairs grow] from the age of nine years and one day until twelve years and one day, and they are still there [when the child reaches twelve, one opinion is that they should be attributed to a] mole, and Rabbi Yossi bar Rabbi Yehuda says they are a sign of sexual maturity. [If these hairs grow] when the child is thirteen years old and one day, then everyone agrees they are a sign of sexual maturity...(Kiddushin 16b)

Pre-Modern Descriptions of Puberty

The way in which children develop into adults has fascinated us for centuries.  In fact, the earliest surviving statement on human growth dates back to the sixth century BCE, (not long after the prophet Jeremiah lived) and is by the Athenian poet Solon. One critic described his poem as combining "scientific sense with philosophical probability (if not, regrettably, with poetic elegance)." Here is Solon:

A young boy acquires his first ring of teeth as an infant and sheds them before he reaches the age of seven years. When the god brings to an end the next seven year period, the boy shows the signs of beginning puberty. In the third hebdomad, [ a period of seven years] the body enlarges, the chin becomes bearded and the bloom of the boy's complexion is lost. In the forth hebdomad physical strength is at its peak and is regarded as the criterion of manliness; in the fifth hebdomad a man should take thought of marriage and seek sons to succeed him. In the sixth hebdomad a man's mind is in all things disciplined by experience and he no longer feels the impulse to uncontrolled behavior. In the seventh he is at his prime in mind and tongue and also in the eighth, the two together making fourteen years. In the ninth hebdomad, though he still retains some strength, he is too feeble in mind and speech for the greatest excellence. If a man continues to the end of the tenth hebdomad, he has not encountered death before due time.

Hippocrates believed that puberty could be delayed in areas where "the wind is cold and the water is hard". Rabbi Shimon ben Gamliel (d. 70CE) would have agreed, because he thought that the growth of pubic hair was hastened in those who used the bathhouse regularly.  But it is especially interesting to compare Aristotle's writings on puberty with those of the Talmud (which of course were codified several hundred years later).

In man, maturity is indicated by a change in the tone of the voice, by an increase in size and an alteration in appearance of the sexual organs, and also by an increase in size and alteration in appearance of breasts, and above in the hair growth above the pubes.

Aristotle (d. 322 BCE) seems to have put a lot of weight on the growth of pubic hair, just like the rabbis of  in the Talmud did many years later. Galen, who died in 199 CE, was cautious about timing the onset of puberty: "Some begin puberty at once on the completion of the fourteenth year, but some begin a year or more after that" (De Sanitate Tuenda, or p288 of this translation). Jumping forward several centuries, we find that girls in Tuscany in 1428 were allowed to marry aged eleven and a half, although they were forbidden to live with their husbands until they were twelve. However the Bishop of Florence (later canonized as Saint Anthony) declared that cohabitation was allowed "provided the girl had reached puberty." 

The Tanner Scale

Today, the stage of sexual maturity in children is most commonly measured using the Tanner scale, described by the British pediatrician James Tanner, who died in 2010.  (He wrote a fascinating History of the Study of Human Growth as a sort of a hobby, but his day job was working as a Professor at the Institute of Child  Health in London.)  Here is how Tanner described his scale in boys, (from his original paper published in 1970):

Stage 1: Pre-adolescent. The velus [sic] over the pubes is no further developed than that over the abdominal wall, i.e. no pubic hair.

Stage 2: Sparse growth of long, slightly pigmented downy hair, straight or slightly curled, appearing chiefly at the base of the penis. This stage is difficult to see on photographs, particularly of fair-headed subjects...

Stage 3: Considerably darker, coarser, and more curled. The hair spreads sparsely over the junction of the pubes. This and subsequent stages were clearly recognizable on the photographs.

Stage 4: Hair is now adult in type, but the area covered by it is still considerably smaller than in most adults. There is no spread to the medial surface of the thighs.

Stage 5: Adult in quantity and type, distributed as an inverse triangle of the classically feminine pattern. Spread to the medial surface of the thighs but not up the linea alba or elsewhere above the base of the inverse triangle.

“There has been less discussion in the literature as to whether the appearance of pubic hair has advanced in females, although this does seem to be the case, pubarche having advanced by at least 6 months. The PROS study found stage II pubic hair to be apparent in African-American females at a mean age of 8·78 years and 10·51 years in whites.”

— Slyper, AH.The pubertal timing controversy in the USA, and a review of possible causative factors for the advance in timing of onset of puberty. Clinical Endocrinology (2006) 65, 1–8

Tanner also described other signs of sexual maturity, since growth of pubic hair is not the only maker.  In boys, for example, Tanner used a five-stage system for genital growth: in stage one, the  "testes, scrotum, and penis are of about the same size and proportion as in early childhood," whereas in stage two, "the scrotum and testes have enlarged and there is a change in the texture of the scrotal skin..."  Tanner noted that the stages of pubic hair development and the stages of genital development differ, so that a boy may reach full genital maturation sooner than he reaches stage five on the pubic hair scale.  

From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45: 13-25.

Tanner's work reveals what we already know intuitively. Maturity, whether sexual or emotional, is a process that takes time and proceeds through many stages. The rabbis of the Talmud relied predominantly on one marker of adulthood:  sexual maturity as evidenced by a minimal of pubic hair growth.  But they used it in conjunction with the age of the child.  They also understood that the onset of these signs might be sooner in some children and later in others.

Sequence of events in puberty in girls (top) and boys. From Marshall A. Tanner JM. Variations in the pattern of pubertal changes in boys. Archives of Disease in Childhood 1970. 45:22.

In most European countries, the age of the onset of puberty (as measured by the onset of menstruation) has fallen by about a year per century. Boys also seem to be developing earlier than previously, possibly by more than a year. Data from the US National Health and Nutrition Examination Survey (NHANES III) study of boys aged 8 –19 years, suggests that the mean age of onset of male genital development based on visual inspection is now about nine years for African-Americans and ten years for white boys.

Another First?

Last year we analyzed talmudic statements of R. Hiyya (who lived in the second half of the second century,) and Rava, (d. 350CE) who appear to have been the first to report an association between obesity and delayed puberty in boys.  They claimed that puberty may be delayed in boys who are underweight, and this association has now been confirmed. As we noted then, none of the researchers has credited these talmudic sages for being the first to notice these associations. But Rava and R. Hiyya were first, and firsts count for something in science. The Baraita in today's daf  may be the first recorded discussion of the lower limits of sexual maturity. But the rabbis of the Talmud used other markers of maturity, like breast development which is discussed in Masechet Niddah (47a).They distinguished between "lower" and "upper" signs of puberty, and so presaged the work of Tanner. (The rabbis also ruled that "all girls who are examined are examined by women". Thank heavens.)

There were several reasons why the Talmud had to codify the stages of physical maturity.  Among these were to allow a father to decide to whom his daughter would marry.

A father who declares...my daughter is twelve years and a day is believed in order to marry the child off...(רמב׳ם הל׳ אישות ב:כג)

Today, any notion that a child under the age of twelve (or sixteen for that matter) would be mature enough to marry is utterly repugnant to us. But according to the UN in developing countries, one in every three girls is married before reaching the age of eighteen, and one in nine is married by the age of fifteen.  When we read the Talmud we often get a glimpse into a Jewish world very different from our own. But some practices of that world still exist outside of the Jewish community today, to the shame of us all. 

From United Nations Children’s Fund, Ending Child Marriage: Progress and prospects, UNICEF, New York, 2014.