The youngest was born in 2019, the same year he was incarcerated (April 2019). Pregnancy lasts 9 months, so even if the child were born in early 2020, there would be no reason to assume infidelity.

I wasn't assuming infedlity, I could have been more clear there. I really was just curious on timing how none of his children could have met him before he was imprisoned.

I was somewhat surprised as well at the phrasing here, and had to look it up. During Assange's time in the Ecuadorian embassy, he fathered two children by a female lawyer hired to be on his defense team. [1]

[1] https://en.wikipedia.org/wiki/Stella_Assange#Personal_life_a...

Not sure how I missed the timing in that Wikipedia note, thanks