There is no such thing as excommunication.  Nothing can separate us from the love of God in Christ Jesus.  Nothing - and certainly not the specter of "excommunication".  As to God creating two genders, the purpose was reproductional.  Since reproduction is (at the moment) expressly forbidden to ordained priesthood, it would seem that gender should play no part in how the faithful are admitted to priesthood.  The simple truth is that current ordination laws forbid more than half the population from receiving one of the Seven Sacraments because they shave their legs and not their faces.  "Either ordain women or stop baptizing them."