What was the last major female original villain they created? Screwball? Paper Doll? Sajani?
It's kind of funny to me that Electro is the only member of the Sinister Syndicate whose male counterpart is dead.
Peter's female villain problem is so bad the Marvel's Spider-Man cartoon had to turn Black Cat into a villain-of-the-week and make Silver Sable Doc Ock's terrorist fangirl.