By now you may be forgiven for suspecting that science is tinted — if not entirely tainted — by politics. The arguments over evolution and global warming alone are enough to make anyone believe that we have red and blue science as well as red and blue states.

But nothing has been quite as polarizing over the past six years as the controversy over embryonic stem cells. Stem cells have been a defining issue even among politicians who can't define them.

So it is no surprise to see a genuine, bona fide scientific breakthrough put through the political spin cycle. Last week, a trio of competing labs from Japan to Massachusetts rolled back the biological clock in mice and turned ordinary skin cells into the equivalent of embryonic stem cells. The research raised the possibility that we might eventually be able to make stem cells without destroying human embryos.

This announcement came on the eve of a House vote to allow federally funded scientists to study cells from leftover frozen embryos at fertility clinics. And this disharmonic convergence put the politicians into orbit.

It tweaked conspiracy theories by embryonic stem cell proponents such as Democratic Rep. Rahm Emanuel, who suggested the irony of having a breakthrough announced every time a bill comes up for a vote. Opponents such as Richard Doerflinger of the U.S. Conference of Catholic Bishops speculated on a higher intervention in his favor. As he said, half-jokingly, "God is telling us He is there!"

The bill passed anyway and now heads to the White House. If the president goes through with his veto, you can bet he'll cite this research as proof that see, told you so, we don't actually need to use human embryos.

Before this happens, let me offer a brief refresher course in Stem Cells 101. What scientists are trying to do is to take an ordinary cell from the human body and persuade it to become, say, a heart muscle cell or a brain cell or a liver cell to fix whatever ails us. But they don't know how to do it.

The reason researchers use embryos is not because they want to run a recycling program for IVF clinics. Nor because they have a passion for wedge issues. It's because the embryo can do what scientists can't do yet. The embryo contains signals that tell the cell to switch on the program of development. But to harvest stem cells, the embryo has to be destroyed.

If, as this latest breakthrough suggests, researchers can reprogram ordinary body cells to act like stem cells in the friendly laboratory mouse, they may eventually be able to avoid the use of embryos at all. Which would be good news all around.

But anyone who says we don't need human embryos in this scientific pursuit has forgotten a couple of things. First of all, we don't know if the new research will work with people. Second, this breakthrough actually began with scientists studying the genes in mice embryos. Anybody who wants to repeat the work in humans will have to use human embryos to learn the same mechanics.

In short, we'll need to use human embryos even to help us eventually stop using human embryos. Pop quiz anyone?

The stem cell debate has been embedded in abortion politics from the get-go, locked into an argument over the moral status of an embryo. Even as science progresses, the politics stay stuck.

Today, as cell biologist Kenneth Miller notes, one side claims "we can do everything we need with adult stem cells." The other side says that "only embryonic stem cells have the full therapeutic potential that we need to save lives." In fact, adds Miller, "Neither side is right. We are far too early in the game to know."

How early? Bioethicist Art Caplan compares us to folks "standing at Kitty Hawk watching the Wright brothers and asking if you can ever get to the moon." Didn't we need a little federal help for that liftoff?

At this early stage we should be pursuing every promising route of research. As Caplan says, "If I were in a wheelchair, I'd want to put my chips on as many numbers as possible."

As the bill heads to the White House, the question is not whether research on embryonic stem cells will go forward. It is going forward in foreign countries and private companies and states that support it from Massachusetts to California. It's whether it will go forward with federal funding and oversight and accountability.

For once in this administration it would be swell to see science trump its bully of a brother: political science.

Write to Ellen Goodman, The Boston Globe, Boston, Mass. 02107 or e-mail ellengoodman@globe.com.