I agree, ths issue is a strict constructionist one.
However, Roe was not decided upon science at the time, unless one means they did so by declaring it also inconclusive.
Roe v Wade makes its decision based on some interesting thinking:
First, it asserts that it is not capable of knowing ancient attitudes toward when life begins, and toward abortion, precisely. But finds no proscription against abortion in ancient religion.
Then it dismisses the hippocratic oath by showing that it precisely reflects only one group's point of view.
Common and Canon law receive the same treatment, as it is able to point to a variety of opinion.
in any case, it does not appear to have based its opinion on scientific evidence, but on the history (or lack) of jurisprudence regarding the matter:
"We need not resolve the difficult question of when life begins. When those trained in the respective disciplines of medicine, philosophy, and theology are unable to arrive at any consensus, the judiciary, at this point in the development of man's knowledge, is not in a position to speculate as to the answer.
"...Physicians and their scientific colleagues have regarded that event with less interest and have tended to focus either upon conception, upon live birth, or upon the interim point at which the fetus becomes "viable,"..."
A beautiful quote from REHNQUIST's Dissent:
"The decision here to break pregnancy into three distinct terms and to outline the permissible restrictions the State may impose in each one, for example, partakes more of judicial legislation than it does of a determination of the intent of the drafters of the Fourteenth Amendment."
http://caselaw.lp.findlaw.com/scripts/getcase.pl?court=US&vol=410&invol=113
I have read the case. I have always viewed the language you quote: "We need not resolve the difficult question of when life begins. When those trained in the respective disciplines of medicine, philosophy, and theology are unable to arrive at any consensus, the judiciary, at this point in the development of man's knowledge, is not in a position to speculate as to the answer. . . . " to say that the state of the science permits the Court to conclude that the state of the science (development of man's knowledge) does not resolve the issue at the point in time the case is decided.
I have thought that your evidence when you tried the case you were going to use as the vehicle to challange Roe would be an overwhelming scientific demonstration that life begins at a very early point in pregnancy; the legal argument would be a response to the Court's language above inviting that kind of case when and if (as it now has) "man's knowledge" extends to the point where science reaches a conclusion.
More important, in my view, is the level playing field issue. If we don't get a level playing field because liberal judges decide that the result dictates the law, the game is over and we will never prevail again--on any issue.
That was the point of Bush v. Gore: The Florida court decided that you count only presumed Gore voters on the recount for the purposes of overturning the majority vote in Florida. You can't have that result because you deprive the voters in Oklahoma of equal protection when they elect electors by counting all the votes; and as well deprive other voters in Florida of equal protection of having all their votes counted also. (Now it wouldn't have worked out that way--subsequent counts demonstrate clearly that whoever you "recounted", Bush still wound up with the most votes. But if the legal result were otherwise and that had not been the vote count, Gore would have been president.)
In the election setting, we want to be clear that everyone is entitled to vote and to have their vote counted. But we want everyone limited to casting only one vote (can't vote twice as many of the double registered Florida voters do); and we think the voters ought to be sufficiently informed so that it is clear who they are voting for. We also think that all voters ought to be real qualified electors (as opposed to individuals voting in the name of dead registrants). Personally, I also see the "walking around money" voters where the Dem's have been paying people to vote for them as an affront to the voting process which ought to come to an end.
A final good example which is an argument for level playing field judges is McCain-Feingold. The campaign finance limitation concept is an effort to preclude non-incumbents from gaining traction in contests against incumbents by raising enough money to buy access. That is what McCain Feingold is all about. A specific directed limitation on the right of free speech which is a fundamental constitutional right the first amendment was designed to protect. Blatently unconstitutional--upheld by the existing court.