I've been living in these United States for well nigh unto 41 years now, and have NEVER seen a female Sean, nor heard anybody opine that they thought the name feminine.

Further, if you see a word in print, how the hell else are you supposed to pronounce it? There aren't Gaelic-American dictionaries on every streetcorner. If you want me to pronounce it phonetically, then spell the damned thing phonetically.

Alex