The Law Code of Parāśara 3.25

Parāśarasmṛti 3.25

yadi patnyāṃ prasūtāyāṃ saṃparkaṃ kurute dvijaḥ /
sūtakaṃ tu bhavet tasya yadi vipraḥ ṣaḍaṅgavit //