Srimad-Bhagavatam: Canto 6 - Chapter 1 - Verse 30
Sanskrit:
सापि तत्प्राशनादेव चित्रकेतोरधारयत् ।गर्भं कृतद्युतिर्देवी कृत्तिकाग्नेरिवात्मजम् ॥ ३० ॥
ITRANS:
sāpi tat-prāśanād evacitraketor adhārayatgarbhaṁ kṛtadyutir devīkṛttikāgner ivātmajam
Translation:
As Kṛttikādevī, after receiving the semen of Lord Śiva from Agni, conceived a child named Skanda [Kārttikeya], Kṛtadyuti, having received semen from Citraketu, became pregnant after eating remnants of food from the yajña performed by Aṅgirā.