What is the basis for Allah's negation of having a son for Himself in the verse: "How can He have a son when He has no consort?" (Quran 6:101), given that having a son does not necessitate having a consort for Allah? And is this an analogical deduction that equates the Creator with the created?

It is not permissible to oppose established fundamental principles by analogizing with ancillary issues. The denial of a consort and offspring for the Lord of the Worlds is affirmed in the Quran and Sunnah, and attributing such to Him is a deficiency and an insult, so much so that "the heavens almost rupture therefrom and the earth splits open."

The verse in Surah Al-An'am refutes the claim of attributing offspring to Allah from three perspectives: 1. He is the Originator of the heavens and the earth, meaning He created them without a prior example. Thus, everything in them is created by Allah, including those whom the Christians claim are sons of God, such as jinn, angels, and Jesus. 2. An offspring only comes into being through birth, and birth requires the existence of a consort. Allah has denied having a consort, thereby nullifying the existence of offspring for Him. 3. He created everything, and this includes all that is claimed to be offspring of Allah. Each of these perspectives is sufficient to invalidate their specious argument.