📖Manusmriti Verse 9.59
On failure of issue, the woman, on being authorised, may obtain, in the proper manner, the desired offspring, either from her younger brother-in-law or from a ‘Sapiṇḍa, descendants
Manusmriti Verse 9.62
But when the purpose of the ‘authorisation’ in regard to the widow has been duly accomplished, the two should behave towards each other like an elder and like a daughter-in-law.
Gautama Dharmasūtra 18:4-6
A woman whose husband is dead and who desires offspring (may bear a son) to her brother-in-law, Let her obtain the permission of her Gurus, and let her have intercourse during the proper season only, (On failure of a brother-in-law she may obtain offspring) by (cohabiting with) a-Sapiṇḍa, a Sagotra, a Samānapravara, or one who belongs to the same caste.
Manusmriti Verse 9.167
If a son is born of the wife of a man, either dead or impotent or diseased, by one who has been duly ‘authorised,’—that son is declared to be ‘kṣetraja’ ‘soil-born.
- Reference Manusmriti Verse 9.59
- Reference Manusmriti Verse 9.62
- Reference Gautama Dharmasūtra 18:4-6
- Reference Manusmriti Verse 9.167
Niyoga in hinduism
If a Hindu women is not having children due to any reason, then it is permissible to get children by having sex with her younger brother-in-law & her Gurus Baba or any hindu male who belong to same caste.