Fan Casting Real Women Don't Wear Dresses in Sort by Tropes

A woman is sometimes shown as weak, incompetent, and ineffectual unless she dresses and behaves in a masculine manner (yet somehow retains elements of her femininity). A variation is a Tomboy and Girly Girl scenario, where the tomboy is presented as superior. It's not hard to spot the Unfortunate Implications; that traditionally feminine traits are weak and worthless and women must "masculinize" themselves to be taken seriously. It takes the old prescriptivist gender roles and merely inverts them, creating a new prescribed gender role that female characters must adhere to or be shunned.