In Hinduism, why is it forbidden to marry a person with the same Gotra? Is it mentioned in the scriptures somewhere? Does it make sense to overlook the restrictions in today's world?
Yes, Sagotra (same-gotra) marriages are prohibited by Hindu scripture. Here's what this chapter of the Manu Smriti says:
- A damsel who is neither a Sapinda on the mother's side, nor belongs to the same family on the father's side, is recommended to twice-born men for wedlock and conjugal union.
And here is what this chapter of the Vasishtha Dharma Sutras says:
- (A student who desires to become) a house-holder shall bathe, free from anger and elation, with the permission of his teacher, and take for a wife a young female of his own caste, who does neither belong to the same Gotra nor has the same Pravara, who has not had intercourse (with another man)
And here is what this chapter of the Gobhila Grihya Sutras says:
- A student, after he has studied the Veda,
- And has offered a present to his Guru (i.e. to his) teacher,
- 3 Should, with the permission (of his parents), take a wife,
- One who does not belong to the same Gotra,
And here is what this chapter the Vishnu Smriti says:
- No one should marry a woman belonging to the same Gotra, or descended from the same Rishi ancestors, or from the same Pravaras.
Many other scriptures say the same thing. In any case, the reason for the rule is that if two people share a patrilineal ancestor, then it's considered a form of incest.