Sayyiduna Ali (may Allah be pleased with him) reports that the Prophet (peace and blessings be upon him) said: "My birth came about through marriage. From Sayyiduna Adam (peace be upon him) onwards, I was never (passed on to the next generation) through fornication, until I was born to my father and mother."
Al-Tabarani recorded it in al-Mu'jam al-Awsat; its chain contains Muhammad bin Ja'far bin Muhammad bin Ali, whose hadith Imam al-Hakim (may Allah have mercy on him) declared sahih in al-Mustadrak, though he has been criticised; the rest of its narrators are thiqat (trustworthy).