Astanga Hrudaya
सन्तो ह्याहुरपत्यार्थं दम्पत्योः सङ्गतिं रहः । दुरपत्यं कुलाङ्गारो गोत्रे जातं महत्यपि ॥ २९ ॥
Wise men say, that in order to beget a (good) offspring, the couple should indulge in copulation in solitude (in a secluded place, free from embrassment by others) a bad offspring, though of reputed pedigree, is like fire to the family.
english translation
santo hyAhurapatyArthaM dampatyoH saGgatiM rahaH । durapatyaM kulAGgAro gotre jAtaM mahatyapi ॥ 29 ॥
hk transliteration by Sanscript