A LOT if the runways have anything to do with it!
Yes, we quake in fear when the words "jeans", "bikini" and "shopping" are uttered in the same sentence, but now we have a whole new dimension to add to this world of jiggly thighs and and butts ... Our stomachs! (Ok... We must take this into account for bikinis also, however I feel it is somehow different with the midriff).
SJP really got things going way back in the days of SATC. Any opportunity she had, that freakishly washboard stomach would be out and proud: whipping us girls into a stomach crunch frenzy that ended in M&Ms on the couch. Given the rest of SJP is whippet thin and verging on Madonna with the muscle-boundedness, I think we all could fairly happily justify ourselves in not looking like her.
It's a different story when it comes direct off the runway and is translated into boutiques, Sportsgirls, department store shelves and diffusion fashion ranges at a shopping centre near you. There is retail pressure to put this stuff on (I find it very hard to say no to sales assistants - I am weak), and then if you're sales assistant is good enough... She'll say "gorgeous" and "stunning" and "looks amazing on you - and I mean that" enough times for you to buy it... Only to have it sit in your cupboard reminding you of your insane purchasing habits all summer. I mean - you can't even wear Nancy Gantz with this stuff!
I think the key to this trend is not baring too much of your stomach in reality - this is not a Britney Spears film clip circa 1999, after all. In which case, there is a chance that this look can be pulled off minus the sucking-in-the-belly all day if the bottom hangs loose, and your top is firmly fitted and long enough to cover your bra (did I really need to tell you that?) and ends just before the end of your ribs. Nothing like a few obvious ribs to make a girl feel skinny about herself, eh?
Is it midriff or bust for you this summer? Or are you going to leave it to the SJP wanna-bes? Part of me would love to go all mid-riffy (in a classy kind of way). The other part of me - that eats - thinks it might be tough to maintain the image of a flat stomach all day.