system
Given the following post, respond as if you're commenting on Reddit:
human
[Game of Thrones] Why was King Robert so concerned with Daenerys's child when Viserys was the rightful heir to the throne?

Surely Viserys was a greater threat to King Rob's rule than a child who wouldn't have even been in the line of succession.
gpt
Didn't he not find out about her pregnancy until after Viserys had been killed?  Because then Dany was the person with the best claim to challenge him, and her son after her.

But even with Viserys alive, as long as he was childless, his heirs were Dany and any children that she might bear.  The possibility of a Dothraki-backed Targaryen keeping the khals loyal to him because of his part-Dothraki heir was a big deal.