Upanishad. In the Jabala Upanishad, Yajnavalkya expounds the four
  asramas. Hence they belonged to the later Vedic period. Meant mainly for
  regulating the life of the male members of the higher castes, they consisted
  of four stages: (a) brahmacharin or student life, (b) grihastha or life of the
  householder, (c) vanaprastha or partial retirement and (d) sannyasin (yati)
  or complete retirement (ascetic life). Full recognition of the fourth stage
  was done only in the post-Vedic period. The Satapatha Brahmana gives a
  detailed description of the upanayana as an important sacrament
Institution of Gotra
Literally meaning cowpen, it came to signify descent from a common
ancestor. It appeared only in the later Vedic period, for it is mentioned for the
first time in the Atharva Veda. This period also witnessed the beginning of
the practice of gotra exogamy. In other words marriage between persons
belonging to the same gotra was prohibited. The notion of gotra appears to
have been particularly important for Brahmins during this period. The gotra
has been regarded as a mechanism for widening the sociopolitical ties, as new
relationships were forged between hitherto unrelated people.
Position of Women
Monogamy (a man having one wife) was very common. Polygamy (a man
having more than one wife), though known, was not common. Polyandry (a
woman having more than one husband), though known, was very rare.
Levirate or niyoga (a dead man’s brother or next of kin marrying the widow)
was practised by some. Remarriage of widows was permitted. Child
marriages were unknown. Women participated in religious ceremonies and
tribal assemblies (sabha and vidata). There was no evidence of seclusion of
women from domestic and social affairs but they were dependent (in the eyes
of law) on their male relations throughout their lives. The system of sati
existed among the Aryans in the Indo-European period. By the time they
entered India, it had, however, gone out of vogue, but it might have survived
in the shape of a formal custom.    Though it is not referred to in the hymns of