My reply relates to cats in general - kittens are basically brats until they mature between 1.5-2 years of age. They will walk right up to an adult cat and swat them in the face, they will jump dogs, they will destroy your belongings, they will do all kinds of aggressive things. It's just the way they operate. And, sometimes, the female kittens get very aggressive towards their male siblings because it's an instinct to not mate with a sibling.
In your situation, you could try observing and then separating them when she gets too aggressive. Distract each of them with toys or treat, something to break the cycle. Eventually, hopefully, she will realize that the male isn't such a threat.
(Assuming there is no medical reason for the female acting this way, of course.)