JK Rowling purses her lips and looks stern on a red carpet.

Please Do Not Let J. K. Rowling Convince You Blood Is Gendered

In today’s spin-the-wheel of transphobic nonsense, fresh from J. K. Rowling’s fevered mental presses, we have a completely false claim that cross-gender blood transfusions are dangerous. Allegedly she discovered this non-fact while doing research for a detective novel—you know, the one featuring a blatant transmisogynistic dog whistle that she wrote under the pseudonym of the man who invented conversion therapy! Sounds extremely legitimate but she did link to a study so let’s dig in.

Recommended Videos

The study Rowling linked to is in fact a real, actual medical study, putting it slightly ahead of some of the other recycled transphobic garbage her fellow ideologues love to spout all over Twitter. But her presentation of both the findings themselves and of those findings as being in any way definitive is misleading at best.

First, the only significant difference in outcomes was found in (presumably cis) male patients who had received blood from (again, presumably cis) female donors. The differences in survival among female transfusion recipients with male donors and recipients whose blood came from a donor of the same assigned sex were negligible.

Further, some of the other findings in this study indicate that there are other, more complex factors involved than just sex matching on blood donations. For example, male patients have significantly lower survival rates overall than women in the ICU, and AKI (acute kidney injury) was found to be more prevalent in patients whose donor matched their assigned sex. The study itself admits:

This was an exploratory study with potential uncontrolled confounders that limits broad generalisation of the findings. Results warrant further studies investigating biological mechanisms underlying the association between donor sex with adverse outcomes as well as studies on the benefit of matching of blood between donor and recipient.

Fortunately, other studies have been done on the matter. Some have found that there is no difference in survival outcomes between patients who received cross-assigned-sex blood versus matched, while others have identified at least one of those “confounders”—pregnancy.

In short, it’s not that AFAB blood is in itself dangerous for AMAB recipients, it’s blood from an AFAB person whose undergone a pregnancy at some point in their life that poses risks. A 2017 study, one which Rowling’s study actually references when discussing possible mechanisms behind their findings, found that while survival rates for AMAB patients who received blood from a never-pregnant AFAB donor were equivalent to those of the other groups those of AMAB patients whose donors had been pregnant at any point went down by 13%.

It’s well established that pregnancy causes immunological changes in a person, even when that pregnancy only has a short duration. One of the best known examples is Rhesus disease, where exposure to the Rhesus antigen via the fetus sensitizes the immune system in Rhesus-negative patients, necessitating an immunoglobulin shot to prevent the immune system from attacking that fetus or potential future pregnancies. Similar, but less extreme, immune responses are formed in the bodies of those who carried a fetus with a Y chromosome, and it’s possible that this may well be what’s causing that rise in mortality among AMAB patients who have received blood from a formerly pregnant donor.

Moreover, these immune system differences already impact how blood donation and transfusion is handled—the NHS doesn’t give AFAB blood to newborn babies in need of a whole blood transfusion because of the risks associated with it. Similarly, there are increasing calls to exclude AFAB blood from use in plasma transfusions for anyone of any assigned sex, (something Rowling’s study actually did), due to the increased risk of transfusion-related acute lung injury (TRALI) as a result of these immunological changes and the antibodies that result. Though not universal, many hospitals and health authorities have already implemented this as much as possible, but a consistent lack of male donors limits their abilities.

Importantly, however, the difference in outcomes is relatively low even for AMAB patients receiving blood from formerly pregnant AFAB donors. What absolutely will kill a patient however is refusing blood until a sex-matched donation can be found. That chronic shortage of male donors mentioned? It’s going to make it even harder to match rare blood types if patients demand a sex match on top of that. This may sound like an unlikely scenario but think about all the absurd demands, refusals of appropriate treatment, and insistence on forgoing basic safety measures that happened (and are still happening because it’s not over yet) during the pandemic.

COVID, much like anything to do with gender, is an ideological matter as much as a base scientific one in the minds of reactionaries and right-wingers. People are already primed to believe anything that reinforces their view of biological sex as an extreme and immovable binary, and this idea that our blood is poisonous to each other ties into that neatly. This kind of misrepresentation of data is dangerous, not just because of the way it ties into anti-trans rhetoric but because anything that furthers medical disinformation and makes it harder for doctors to do their jobs costs lives.

(featured image: Neil Mockford/FilmMagic)

The Mary Sue is supported by our audience. When you purchase through links on our site, we may earn a small affiliate commission. Learn more about our Affiliate Policy
Image of Siobhan Ball
Siobhan Ball
Siobhan Ball (she/her) is a contributing writer covering news, queer stuff, politics and Star Wars. A former historian and archivist, she made her first forays into journalism by writing a number of queer history articles c. 2016 and things spiralled from there. When she's not working she's still writing, with several novels and a book on Irish myth on the go, as well as developing her skills as a jeweller.