What is the age of bulūgh for boys and girls in Islam?
The term bulūgh is commonly translated as ‘puberty’ or ‘maturity’. It represents the stage when a Muslim boy/girl is old enough to have the capacity to take on Sharia responsibilities (takālīf). According to Muslim jurists, it becomes incumbent upon Muslims to follow and act in accordance with all the ordinances of Sharia after they have attained bulūgh, whereby if they were not to do so then they can be held accountable in front of God or even an Islamic court. The age of bulūgh that is usually stipulated for Muslim boys is between 14-15 years, whereas the age of bulūgh that is usually stipulated for Muslim girls is between 9-13 years.
Sharia responsibilities that become incumbent upon a Muslim after attaining bulūgh can generally be divided into two types:
- Devotional responsibilities (ʿibādāt), which refer to spiritual acts of worship such as daily prayers (ṣalāt), fasting (ṣawm), and performing pilgrimage (ḥajj).
- Non-devotional responsibilities (muʿāmalāt), which refer to commercial and civil acts that involve interaction and exchange among people such as sales, marriage, divorce, and criminal punishments.
The major question that arises regarding the issue of bulūgh is whether everyone who is aged between 9-15 capable of performing a wide-range of devotional and non-devotional Sharia responsibilities? In other words, are the stipulated ages of bulūgh universally applicable across all contexts and all Sharia responsibilities? Or do/can they change or vary based upon different contexts and sharia responsibilities?
Islam does not stipulate a single age of bulūgh that is universally applicable across all contexts and sharia responsibilities. Non-devotional Sharia responsibilities (muʿāmalāt) are solely dependent upon the law of the land and hence, the age of bulūgh is determined by the given social convention of where an individual resides. Meanwhile, the age of bulūgh for devotional Sharia responsibilities (ʿibādāt) is determined by the physiological changes that take place in the individuals’ body, such as seminal discharge for boys and menstruation for girls. However, there is no obligation to perform any duties unless the ability of enactment (wusʿ) is ascertained.
1. The Quran mentions the notion of bulūgh in four different manners, and the verses that describe the notion of bulūgh can be grouped into four sets.  These verses generally use the notion of bulūgh in relation to non-devotional Sharia responsibilities. However, there is no verse in the Quran that stipulates a specific age for bulūgh. Furthermore, with regards to devotional Sharia responsibilities, such as praying, fasting, and performing pilgrimage, the Quran does not stipulate the general condition of bulūgh. In fact, the overarching notion that the Quran espouses in numerous verses is that of wusʿ,  in accordance with which Allah only makes Sharia responsibilities incumbent upon individuals who possess the ability to enact them. Therefore, the Quran does not stipulate a ‘specific age’ as a criterion for when Sharia responsibilities become incumbent upon a person, rather it emphasises ‘ability’ as the overarching criteria.
2. In contrast to the Quran, narrations set the condition of reaching bulūgh as a requirement for both non-devotional and devotional Sharia responsibilities. Whilst the Quran does not stipulate specific indications of when an individual reaches bulūgh, these specific indications are given in seemingly contradictory hadith narrations. These hadith narrations specify two different indications that enable the discernment of when an individual reaches bulūgh:
- The first indication is bio-physiological changes, which in males are discerned through signs such as seminal discharge, the growth of pubic and facial hair, and the deepening of the voice. For females, these changes are discerned through signs such as the commencement of menstruation, changes in the voice, and the growth of pubic hair.
- The second indication is when males reach 13 or 15 lunar years of age and females reach 8 lunar years of age.
The fact that the hadith narrations point towards two different indications highlights that there is no fixed criterion for discerning when a male/female reaches bulūgh. Rather, it suggests that the criterion is fluid and may be specific to individuals in different contexts. This is supported by the fact that according to sociological studies, the time when puberty begins varies greatly among individuals; puberty usually occurs in girls between the ages of 10 and 14 and between the ages of 12 and 16 in boys. 
3. Since the hadith narrations point towards two differing indications for discerning when a male/female reaches bulūgh, and since the Quran does not stipulate any specific indication to discern bulūgh (but rather places emphasis on ability (wusʿ)), it is established that in Islam the most important criterion for determining when Sharia responsibilities become incumbent on an individual is when he/she has the ability to enact them.
While differing abilities are reached at differing stages of life for different people, it is impossible for a social community to function coherently without setting universal standards for all its members. The universal standards that are set by different societies for different responsibilities are not arbitrary, but rather are established on the basis of the aptitudes and abilities displayed by most members of each society. Accordingly, with regards to non-devotional Sharia responsibilities (muʿāmalāt), which involve socio-communal interaction and exchange among people, the stage when an individual is deemed to have attained ability (wusʿ) should be determined by the convention of where that individual is located. For instance, if an individual resides in a location where the age of marriage is set at 18, then for this person the Sharia marriage should take place at 18 and not before that, as they would only be considered to have the ability to enact the responsibilities of marriage at that age and not before it.
In contrast to non-devotional Sharia responsibilities, devotional Sharia responsibilities (ʿibādāt) do not involve socio-communal interaction and exchange among people. Rather, they are practices of a spiritual nature, and thus it is difficult to measure when an individual attains the ability to enact them. Accordingly, the universal standard for when an individual attains the ability to enact devotional Sharia responsibilities is determined by the physiological changes that take place in the individuals’ body, such as seminal discharge for males and menstruation for females. However, after experiencing these physiological changes, if an individual feels that they do not possess the ability to enact a devotional responsibility, then there is no obligation upon them to do so. For instance, in the United Kingdom, the average age of when a female goes through physiological changes is 11, and at this age she may have the ability to perform the Sharia responsibility of daily prayers (ṣalāt) but may not have the ability to perform the Sharia responsibility of pilgrimage (ḥajj), as the enactment of pilgrimage is more strenuous than the enactment of daily prayers.
 The first manner is īnās al-rushd (discerning maturity) see Quran 4:6. The second manner is bulūgh al-ashudd (reaching the age of physical development of the body) see Quran 6:152, 12:22, 17:34, 28:14, 46:15, 22:5, 40:67, 18:82. The third manner is bulūgh al-nikāḥ (reaching the age of sexual potency) see 4:6. The fourth manner is bulūgh al-ḥulum (reaching the age of puberty) see Quran 24: 58-9.
 See Quran 2:233, 2:286, 6:152, 7:42, 23:62. Other similar principles discussed in the Quran include; yusr (ease) see Quran 2: 185; takhfīf (mitigation) see Quran 4:128; nafī al-ḥaraj (non-hardship) see Quran 5:6.
 See Wasāʾil al-Shīʿa, 1:42-46; Al-Kāfī, 4:276, 7:69 and 198; Masā’il ʿAlī b. Jaʿfar, p.308; Tahdhīb al-aḥkām, 2:381, 6:310, 7:383; Al-Faqīh, 2:122; Ḥurr al-ʿĀmilī, Tafṣīl wasāʾil al-Shīʿa, 20: 101, 104, 494 and 22: 103, 130
 See the commentary on Quran 4:6 in al-Ṭabarsī’s Majmaʿ al-Bayān; Faḍlallāh, Tafsīr min Waḥy al-Qur`ān
 For average age of puberty see https://www.medicinenet.com/puberty/article.htm#puberty_facts
 For the commencement of puberty for females see in the United Kingdom see https://www.nhs.uk/conditions/early-or-delayed-puberty/