Why don't female teachers accused of "inappropriate relationships" with male students simply cry "rape"?

I mean, I've never heard of a single case of a female teacher accused of an inappropriate sexual relationship with a male student simply saying that they were assaulted, and that it wasn't consensual. Why not, exactly? Surely, it would be perfectly possible, even rather likely, for a sixteen year old boy to physically force a 24 year old lady teacher. And, who could possibly prove that this isn't exactly what actually happened? So, why aren't these lady teachers simply crying "rape" to defend themselves in cases of accusations from male students?