Among North Indian Hindus the marriage between brother and sister is not allowed for seven generations from father side and three generations from mother's side, but among South Indian Hindus particularly among Brahmins cross-cousin marriage is prevalent (i.e. a boy can marry the daughter of his maternal uncle). What is the reason behind this? Does any Hindu scripture illuminate on this issue ?
I am answering only this part:
Does any Hindu scripture illuminate on this issue?
Most of the customs in Hindu families are practiced according to Dharma-Shastras and Grihya-Sutras. Baudhayana Dharmasutra, PRASNA I, ADHYÂYA 1, KANDIKÂ 2 declares that people from South India can marry with the daughter of their maternal uncle.
We will explain those (peculiar) to the south.
They are, to eat in the company of an uninitiated person, to eat in the company of one's wife, to eat stale food, to marry the daughter of a maternal uncle or of a paternal aunt.
But there is one condition that, the above practices can be followed only in prevailed country.
- He who follows (these practices) in any other country than where they prevail, commits sin.
In fact it is not a north-south divide among Hindus on the practice of cross-cousin marriage but a divide of RigVedic culture and a culture evolved in north India under later Hinduism. Let us understand it stepwise :- 1. Incest taboo or barring milk relation - In the ancient times Hindus of RigVeda period were, perhaps, first to bar milk relation in marriage.As, RigVeda tells us through a dialogue between twin brother sister Yam and Yami ( ref. RV.10.10.(1-14). Here Yami wants to stick to a old tradition and asks Yam to produce child through her but Yam firmly denies her refering to the rule and vigilance of Asura/Varuna. While in European countries incidences of incest relations are reported to be practiced up to recent past. However, Muslim still holds that barring milk relations code in marriage. 2. Barring blood relation - with the emergence of paternal family system, a concept of blood relations emerged which envisages that offsprings carries blood of father and not that of mother. Thus the barring of milk relation was extended to the barring of blood relation. Here we find the origin of cross-cousin marriage. In RigVeda we don't find description of such marriages nor we should expect to find everything in it, but we certainly find a concept of lineage based on blood relation in varous hymns refered as 'tokasya tanye'. Here I assume that the cross-cousin marriage system must be a part of RigVedic culture and must be a practice at pan-India level among Hindus. 3. My assumptions are based on both textual evidence and data generated during my field studies. Various ethnographic studies suggest that in north India a joking relationship is allowed between a man and the wife of his maternal uncle but strictly prohibited with the wife of his paternal uncle. And tradtionally maternal uncle had a greater role in the decision making in marriage of a boy or girl.This could be a vestige trait of pre existing cross-cousin marriage. My field study, in the upper reaches of Uttarkashi district of Uttarakhand state where fraternal polyandry(Draupadi vivah) is still practiced, was revealing. Not only I found some cross-cousin marriages but also learned that it was a prefential practice in the recent past. They also celebrate 'Vishu' festival which is also celebrated in Kerala with same name and same date, while in north India different name is used. In general we find that South India still retain most of the RigVedic cultural traits viz. 'YAKSHA GAN' of Karnataka, worship of 'INDRA DHWAJ' before starting classical dance while innovative North Indian Hinduism evolved new cultural practices like ' BURNING RAVANA'