Manusmriti

siva.sh/manusmriti/9/147

या नियुक्ताऽन्यतः पुत्रं देवराद् वाऽप्यवाप्नुयात् । तं कामजमरिक्थीयं वृथोत्पन्नं प्रचक्षते ॥ १४७ ॥

sanskrit

If a woman (duly) appointed bears a son to her brother-in-law or to another (Sapinda), that (son, if he is) begotten through desire, they declare (to be) incapable of inheriting and to be produced in vain.

english translation

yA niyuktA'nyataH putraM devarAd vA'pyavApnuyAt | taM kAmajamarikthIyaM vRthotpannaM pracakSate || 147 ||

hk transliteration by Sanscript