Level the forests. Reduce everything to smooth, hard certainty. The problem isn't just gender. It's way past something as simple as gender. Female leaders are stand-ins for our own mothers.
Mothers control our deep-down emotions.
In World War II, allied soldiers knew how to break even the toughest German spy who refused to talk. That's all it took to reduce the toughest spy to a blubbering mass. Mothers have enormous, almost mystical power over us. And a female leader is a painful reminder of that. But the more you look at this taboo, the weirder it gets.