I know he had them for a time pre-Civil War, but why wasn't organic web spinning one of the powers Peter Parker got when he was initially bitten by the radioactive spider? His strength, agility and wall-crawling are all abilities that spiders have. I would argue that above all, a spider is known for spinning webs and Parker should have developed that natural ability as well, instead of having to invent his own webbing fluid.
With all his other powers, was natural webbing too much for a single hero in the 60's?
In recent Amazing Spider-man comics, Peter meets a girl named Cindy that was bitten by the same radioactive spider he was and she has natural web spinning powers (Amazing Spider-Man Vol 3 #4). How can that be?