Brihat Parashara Hora Shastra
सुतेशे चरराशिस्थे राहुणा सहिते विधौ । पुत्रस्थानः गते मन्दे परजातं वदेच्छिशुम् ॥ १४॥
If Putr‟s Lord is in a Movable Rāśi, while Śani is in Putr, as Rahu is with Candr, the child (so born) is of questionable birth.
english translation
suteze cararAzisthe rAhuNA sahite vidhau । putrasthAnaH gate mande parajAtaM vadecchizum ॥ 14॥
hk transliteration by Sanscript