Board Thread:Questions and Answers/@comment-28702329-20180609141525/@comment-38085160-20190107120940

Also, The World isn't a byproduct of the Joestar bloodline. It's the reverse. If anything, Star Platinum is probably a byproduct of The World and Jonathan combined. That would honestly make more sense to me, considering Star Platinum looks more like Jonathan than The World does.

Except that when Star Platinum first shows up in the manga, it looks like Jotaro in cosplay armor & longer hair. The facial expressions even mirror Jotaro's exactly at first. Then they become the emotions that Jotaro isn't showing on his own face (at one point Star Platinum destroys something with a broad grin on it's face while Jotaro keeps his usual ironic expression). It's only quite a bit later that Star Platinum starts looking like an android because Araki decided all the Stands should have a mecha look. Then its face diverges from its Jojo.