Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 12: Preparation for the Aśvamedha Sacrifice
Text 1.12.8

मम लालप्यमानस्य पुत्रार्थं नास्ति वै सुखम्।
तदर्थं हयमेधेन यक्ष्यामीति मतिर्मम॥

mama lālapyamānasya putrārthaṁ nāsti vai sukham
tad-arthaṁ
haya-medhena yakṣyāmīti matir mama

mama lālapyamānasya = I have been continuously in a state of lamentation; putra-artham = because of wanting a son; na asti vai sukham = with no happiness; tat-artham = to get a son; haya-medhena = in an Aśvamedha sacrifice; yakṣyāmi = I should engage; iti = that; matiḥ mama = therefore, I have concluded.

I have been continuously in a state of lamentation with no happiness because of wanting a son. Therefore, I have concluded that I should engage in an Aśvamedha sacrifice to get a son.