By some sense, all superhero costumes, male or female are mostly sexy,
because the physiques etc of male or female superheroes is really what you're looking at. The drawing of the "costume" is just... drawing, lines and colors.
So those things will draw attention or enhance, breasts, but even without lines and colors, the image of breasts, strong chests, butts, etc are still there.
Only capes, skirts, etc disguise the form.
They're really all naked, actually.