Common sense is just basic reason, and quite useful, ESPECIALLY for human behavior. It has limitations (e.g. complex dynamics, particularly with counterintuitive outcomes) but serves well if we recognize those limitations. Recognizing limitations of not just our knowledge but means of acquiring it is also useful. At the risk of a tangent, I cannot help wishing schools spent more time on division by zero so people do not forget it exists, or expect to define it "someday, when we know more."

In this case, we have conflicting data: One study of a large but incomplete group shows a positive correlation between contraception use and sexual activity, but another study of a large partially overlapping group shows a negative correlation. Absent additional studies, preferably of ALL people rather than just those with low incomes or in their teens, firm conclusions FROM DATA are impossible. However, FROM LOGIC, we can indisputably say increased contraception use in no way deters sex, which most people enjoy (though I do not have any data handy to support that "proposition.") Thus contraception can ONLY encourage sexual activity.

While increased contraception use significantly reduces the risk of pregnancy, and therefore a deterrent to sexual activity, I have not seen even a speculative suggestion of why it would encourage sexual activity, so it is hard to see how it could cause the reduced sexual activity in the study you cited. The most logical explanation is probably that promoting abstinence and other things styled as "oppression" actually HAVE increased teen abstinence, though increased awareness that contraception is imperfect may have been a factor also. That should not obscure the fact promoting abstinence remains an inadequate solution to teen pregnancy, because many teens will disregard it, and thus the proper use of birth control, along with its risks and limitations, should be taught in school health classes.

I suspect it depends on how one defines "miscarriage." Since preventing uterine implantation of fertilized eggs is a primary goal of IUDs, they SHOULD raise rates of "spontaneous abortion" as defined by those who believe life begins at conception: That is the POINT. If they do not, they are just uncomfortable placebos. What is critical is that is one small part of a "life begins at conception" article premised on promoting effective contraception. It is proof of pro-contraception members of even the strictest pro life factions, which makes categorically dismissing all pro lifers as anti-contraception unfair and inaccurate.

Ryans legislation earned many pro life critics; they do not necessarily represent "the movement at large." It is VERY "large," with widely disparate views, the point I (and nossy) have tried to convey. Just a couple days ago I saw a story about a pro life group assailed by far right pro lifers for promoting the anti-mercury campaign as "pro life." It basically went as one would expect; some critical pro life groups even took a moment to explicitly deny global warming along the way. Part of the problem is the sheer size of the pro life movement that not only creates great diversity, but attracts demagogues who care no more about fetuses than about babies, far less than they care about a way to rally millions to their far right agenda. This covers that well: http://www.youtube.com/watch?v=o1PUFNZgWD0

Separate, but related. You led off mentioning the contention abortion is murder and the following sentence noted murder has moral precedence over birth control. Miscarriage was only referenced as a medical rather than legal concern ONCE, auxillary to the initial argument and preliminary reinforcing it by pointing out the rarity of "legislator[s]... trying to criminalize miscarriages." That was the second (and only other) mention of miscarriages, and even that was in the context of law, not medicine. So, yeah, if three of five sentences in a paragraph that begins and ends discussing law are also about law, and only one of the remaining two is about medicine, I am unlikely to conclude the paragraph is about a medical epidemic. Do I really need to explain how paragraphs work? I take it you remain unconvinced self-righteous condescension will not persuade pro lifers to alter their position. From what I can tell, you, I and nossy are in basic agreement on the legal and policy issues, but the reaction from pro choice people like us suggests your advocacy could use improvement.