Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 8: Daśaratha Decides to Perform the Aśvamedha Sacrifice
Text 1.8.12

सर्वथा प्राप्स्यसे पुत्रानभिप्रेतांश्च पार्थिव।
यस्य ते धार्मिकी बुद्धिरियं पुत्रार्थमागता॥

sarvathā prāpsyase putrān abhipretāṁś ca pārthiva
yasya te dhārmikī buddhir iyaṁ putrārtham āgatā

sarvathā = certainly; prāpsyase = you will; putrān = have sons; abhipretān ca = as you desire; pārthiva = O king; yasya te = since you have; dhārmikī = dhārmika; buddhiḥ = idea; iyam = this; putra-artham = to obtain a son; āgatā = come upon.

O king, since you have this dhārmika idea to obtain a son, you will certainly have sons as you desire.

“Sons” in the plural because having one son is as good as having no son. Besides, one should endeavor to have many sons [1].

[1] eṣṭavyā bahavaḥ putrāḥ.