Heretic?  Are you serious?  Heresy is the negation of a dogma.  What dogma are we discussing?  Please cite a real dogma, a real infallible definition, not papal executive orders or ecclesiastical fake news.

As far as I know, the only dogmatic definition we have about the sacramental priesthood is the one given by Trent.  It doesn't mention a masculinity requirement for apostolic succession, so it remains an open question.