Jatakaparijata 13.19

13.19

atha sutādiyogakarī grahasthitiḥ |
aṣṭamāṣṭamage sūrye niṣekarkṣātsutodbhavāḥ |
athavā'dhānalagnāttu trikoṇasthe dineśvare ||

Now, the planetary configuration producing sons and other offspring:
Offspring are born when the Sun is in the eighth from the eighth from the sign of impregnation,
or when the lord of the day is situated in a trine from the ascendant of conception.