[QUOTE=NinjaChick]
Yeah, but doesn’t it ignore the fact that periods are a gruesome PITA?
Tangential: I’ve noticed, in my dramatically limited observations of the issue, a sort of mini-generation gap on the issue of intentionally skipping periods via birth control. I think that younger women are at least okay with it, if not all for it, because we’ve reached a point as a society where not only is it okay to openly say that yes, periods are a pain to deal with, but also to go as far as to do something about it. It’s finally acceptable (well, to most people at least) for a woman to take control of her body, rather than being a slave to it.
I find that, on the other hand, my mother’s generation - again, in her particular case, the all-talk-no-action, march-on-Washington, bra-burning generation of feminists - it’s maybe okay to not be thrilled with your monthly period, but it’s still weirdly revered. Messing with it is somehow “giving in” to some sort of oppressive force, and that in and of itself is shameful.
Or I could just be totally talking out of my ass, as lately I’m on a kick of realizing that the world is an absolute mess and it’s very much the fault of my parent’s generation. So there. 
[/QUOTE]
I think, among educated people anyway, the period-skipping divide is actually the result of a schism in the medical community and the rethinking of what “natural” means.
For years, it was thought that skipping periods was unnatural, and therefore unhealthy. If you didn’t release the endometrium once a week as God and Nature intended, who knows what might happen?
Then someone thought about it a little more and went, “Wait a minute. Women ‘in nature’ hardly menstruate at all! ‘Natural’ women, without access to contraception, are either knocked up or nursing on demand, and in both of those states, they’re not menstruating!” Some research with third world tribal living women revealed that most of them had fewer than 50 periods in a lifetime, between their pregnancies, nursing on demand and simple sub-par nutrition. They also have far lower incidences of uterine and endometrial cancer, as do multiparous women in developed countries, partly because they spend so much time not menstruating.
So people using the old definition of “natural” (which tend to be older women and doctors) think skipping periods is unnatural and unhealthy. People using the new definition of “natural” think that having all those periods is unnatural and unhealthy.
ETA: Dagnabbit. Too many words = beaten to the punch. Ah well.