Stan Lee Blocked What Would Have Been X-Men's Most Powerful Female Hero

screenrant.com:

An interview with Roy Thomas — an early X-Men writer and the creator of major mutant heroes including Wolverine, Havok and Sunfire — confirms that then-editor Stan Lee blocked the creation of what would have been the franchise's most powerful female character, mandating that they should be a man instead.

Thomas wrote The X-Men volume 1 from #20-43, taking over from Stan Lee, who created the team along with acclaimed artist Jack Kirby. Thomas introduced a host of still-popular characters, including several core members of the 'Second Genesis' team, who revamped the franchise from its original team of teen heroes. However, it turns out that one of these characters was originally pitched as what would have been the franchise's most powerful female mutant.

Related: X-Men Needs to Bring Back Emma Frost's Forgotten (But Perfect) Codename

The character in question is Banshee, aka Sean Cassidy, a former Interpol agent who has worked with the team on many occasions, but originally encountered them as a villain under the control of the Ogre (in Thomas and Werner Roth's 1967 X-Men #28.) Most notably played by Caleb Landry Jones in X-Men: First Class, Banshee is able to emit a piercing shriek, with a costume specially designed to fly at incredible speeds by harnessing his natural harmonics. However, in an interview with AIPT for 'X-Men Monday #159,' Roy Thomas confirms past comments that the character was originally conceived as an incredibly powerful woman who would have taken on the five original members of the mutant team (Cyclops, Marvel Girl, Angel, Beast, and Iceman):

So I liked the name Banshee and I thought that would make a good character, except Stan wouldn’t let Banshee be a woman. Stan said you can’t have five X-Men