From the Gawker science blog io9 comes a particularly cool revelation about pregnancy that might seem apolitical at first glance, but holds powerful implications for one of the abortion movement’s more callous talking points:

Researchers have known for some time that women who experience weakened heart function in the months before and after childbirth (a condition known as peripartum cardiomyopathy) recover more quickly than any other group of heart failure patients. Now, a team of researchers from Mt. Sinai School of Medicine thinks it may know why.

The researchers have demonstrated that when a pregnant mouse suffers from a heart attack, her fetus will actually donate cells that can migrate to mom’s heart before differentiating into different types of cardiac cells, aiding in the heart’s regenerative processes.

Every once in a while, a pro-choicer trying to sound clever will make the argument that, while unborn babies may be living things, they’re basically parasites from which the “host” is perfectly entitled to defend herself. Consider Joyce Arthur of the Pro-Choice Action Network:

In fact, the biological definition of “parasite” fits the fetal mode of growth precisely, especially since pregnancy causes a major upset to a woman’s body, just like a parasite does to its host. I’m not trying to disparage fetuses with the negative connotations of the word parasite; in fact, parasites and their hosts often enjoy mutually supportive relationships, and this would include most pregnancies. However, the parasitic relationship of a fetus to a woman means that its continued existence requires her consent[13] – if she continues the pregnancy unwillingly, her rights and bodily integrity are violated. Fetal dependence on a woman’s body also refutes the common anti-choice assertion that fetuses are “innocent” and therefore deserving of protection. An unwanted fetus has no ill intent of course – like a parasite, it’s just doing what it naturally has to do – but the physical risks of pregnancy and its total disruption to a woman’s body and life means the fetus is not harmless, and therefore not innocent.

There are, of course, numerous problems with that argument. For one thing, the fetus is a member of the same species as his or her mother, and therefore can’t be thought of as simplistically as you would a lower order of creature, like a tapeworm, invading your body. For another, fetuses aren’t foreign entities, but the natural result of the human body functioning correctly. Doesn’t the act of creating the “parasite” constitute at least tacit consent for it to take up residence inside you?

But the Sinai study demonstrates that the relationship between mother and unborn child can be more than just “mutually supportive.” Many mothers will discuss the intangible benefits of their pregnancy—joy, purpose, fulfillment, etc.—but if the study is correct, the mother also gets something much more quantifiable out of the deal: babies have the potential to actually heal their mothers, perhaps even save their lives, from within the womb. And that’s not the only known health benefit of pregnancy, either. How long will it be before we discover even more astounding ways that babies’ stem cells help their mothers?

That’s not to deny the difficulties and potential dangers of pregnancy, of course. But let’s give credit where credit is due—does the above really sound like a parasite?

Those looking for new biological terminology to describe pregnancy would be better off ditching “parasitic” for “symbiotic”: two organisms living together for mutual benefit. Think that’ll make it into Planned Parenthood’s educational efforts?