Vratyastoma is a ritual performed by Vratyas (people who have failed to perform Upanayana in time) to readmit themselves to the fold of Varnashrama Dharma. Many Westerners who convert into Hinduism perform this ritual. However, Sri Sri Sri Chandrasekharendra Saraswati MahaSwamiji in his book "Hindu Dharma" says:
If the Gayatri has not been chanted for three generations in the family of a Brahmin, its members lose caste (they cease to be Brahmins). The quarter where such Brahmins live cannot be called an "agrahara". It is perhaps not yet three generations since Brahmins gave up the Gayatri. So they still may be called Brahmins.
In the same way if the Brahmin family has not performed sacrifices for three generations its members will be called "Durbrahmanas", degenerate Brahmins. Even though degenerate the label "Brahmin" sticks to them. There are prayascittas (expiatory rites) by means of which the corrupted Brahmins will be remade true Brahmins. But there is no such hope for a Brahmin in whose family Gayatri has not been chanted for three generations. A member of such a family ceases altogether to be a Brahmin and cannot be made one again. He is just a "Brahmana- bandhu", a kin or a friend of Brahmins. The same rule applies to Ksatriyas and Vaisyas with regard to the Gayatri mantra; they become "ksatriya-bandhus" and "Vaisya-bandhus" respectively.
Do any scriptures validate MahaSwamiji's claim that families where the Gayatri Mantra has not being chanted for 3 generations cannot return to the fold of Varnashrama Dharma?