Usually to be defined as child sex abuse I think w for most authors there'd need to be some kind of discrepancy in the ages in some way, that is y'know if somebody was about thirteen and the other person was about eighteen it might be ah starting to get er a big enough discrepancy to be outside the realm of of y'know kind of normal y'know sort of boyfriend and girlfriend to use those saccarinous terms erm relationships and maybe might be considered to be er to be something like child abuse.
