What is *up* with all the gender-swap fics lately? And not the occasionally fun and amusing so-and-so gets turned into a girl (or a guy, though that's actually very uncommon) and wacky-hijinks ensue kind, but the 'so-and-so main character was born a girl' kind. I mean, the 'gets-turned-into' kind is usually either hilarious or a horrifying study in anti-feminism (because, clearly the first thing any guy is going to do upon becoming the opposite gender is to become the ultimate cliche girly-girl, acquire a new personality (or lack thereof), and either a new sexual preference or discover that their usual love-interest is a closeted lesbian). Very rarely is the gender-swap thing done in a way that is either believable or realistic (I've seen a few Stargate fics that actually are both, yay for cannon wacky Ancient tech insanity) and most of the time it's just an excuse to have a yaoi relationship without it technically being 'yaoi' by squemish newbie fangirls who think they're being clever.
This 'main character is *born* female' thing that seems to be all over fandom (I've seen it in Naruto, HP, DGM, and a few other places as well) appears to be both a 'lets have a yaoi couple without the gay' thing and a 'lets insert my oh-so-very-cool original character in the place of the main character, keep some of said characters background angst or give said character *more* angst because angst is the most attractive and fun to read thing ever and pair said character up with so-and-so male character because he's so awesome' thing, aka a not so very cleverly disguised Mary Sue. I mean, I *suppose* that it might be possible that one or two of these fics may be a valid AU whereupon said main character genuinely was born female and is still essentially the same character with minor differences (because realistically there would be some character differences if born a different gender, but not to the point where the character is completely unrecognizable and suspiciously is 'so-much-cooler' than cannon) but it's very unlikely except in the case of dimensional travel whereupon the MC travels to a universe where he was born female- because those ones are usually done well, or at least aren't Mary Sues.
Still, if you're going to write yaoi or a Mary Sue, then just do so- don't try to get around or hide it by destroying perfectly good cannon characters (though considering how OOC all the other characters usually are in said fics, maybe it's a mercy for said characters to be 'killed' and replaced by a defective wrong-gender quasi-clone (because usually appearance, name, and most defining characteristics are erased as well, other than a few physical points such as a scar or tattoo, or seal of some sort). If only people would stop spamming fandom with this new trend... if I want to read a fic staring Naruto, or Allen, or Harry, then I *don't* want to read a fic staring Naruko, Alanna, or Harietta - or Kelly, Melissa, and Chrysanthemum, because half the time they don't even bother to keep the 'new' names anything close to the old, and in the case of anime, the names are either mysteriously western or clearly borrowed form another popular anime (you can tell, because said names are usually uncommon or unique in Japanese to begin with). You aren't as clever as you think you are fangirls and boys.