If one is not purified by the process of the seed giving ceremony, or garbhadhana samskara he is immediately classified amongst the sudras because only the sudras do not undergo this purificatory process.
Krsna book, IIp.236
The pious seminal succession in the twice born families of the brahmanas and ksatriyas especially, as well as in the families of vaisyas also, must be kept very pure by the observation of the purificatory process (samksaras) beginning with ga

27 July, 1973