You have wings already?
The proper way to manage knights (and mobilization) is to keep your infamy down. Way,
way down. Each point of infamy
level (the number after raw infamy in the main map screen) gives +5% chance that a knight will spawn each month. If you have under 5 infamy, there will be
no knights.
It's basically a magical condom. Some people prefer to bang their favourite captives without impregnating them, I guess as a form of stress release? Because there's no such thing as dragon love, no, definitely not...
Note that the actual impregnation
can also use mana to get better minions. But that's where virility comes in. Read a page or two back, it just got explained in some detail.
No, your minions think you're a pushover.
Too many of them can cause this, but not only and not with all minions.