Just to throw a random argument out there that I probably won't defend....
If Jesus had a child, then that would imply that he had sex. In order to have sex, one must be a sexual being with sexual desires. If one has sexual desires, then surely they lust after other people.
And we know what the Bible says about lust:
Job 31:11-12: For lust is a shameful sin, a crime that should be punished. It is a devastating fire that destroys to hell. It would wipe out everything I own.
and
Matthew 5:28: But I say, anyone who even looks at a woman with lust in his eye has already committed adultery with her in his heart.
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