All about mpreg in fandom! a surprisingly popular niche

Today, let’s dive in a subject a lot of us heard about, but might prefer to ignore… Mpreg! As in, male pregnancy (learn more on the Fanlore page). Yup. As usual, we studied fanfictions that are 10K+ words.

Mpreg is kind of a controversial fanfiction subgenre: people are either fascinated or put off, with very few stance for a middle ground. On AO3, actually a tiny minority of fics are labeled mpreg: in 2015, we counted 1357 fics tagged with mpreg published on AO3, that is 1.9% of the total of 10K words + fics. However, those fics are widely read: they attract way more readers than their number alone would predict.

A minor but popular subgenre

Mpreg on A03 is highly concentrated in a small number of highly popular fandoms.

There were only 11 fandoms with at least 20 fics tagged mpreg in 2015. However, even if mpreg stories are a small minority of fics, they have better visibility: they attract more hits, more kudos and more bookmarks on average than other fics.


For example, 5% of all fics of more than 10K words published on AO3 in the Supernatural fandom were labeled mpreg. This is much higher than the average proportion of 1.9%, all fandoms combined. But these mpreg fics attracted a disproportionate amount of bookmarks (10%), of kudos (10%) and of hits (14%).


It could be because mpreg stories are not distributed uniformly across the fandoms. They could occur more often for very popular ships, and thus benefit from the popularity of those ships. However, inside specific ships also, mpreg fics are more popular than other fics.

Here are the statistics for the 9 main ships with at least 20 fics tagged mpreg in 2015. Mpreg fics still attract a disproportionate amount of bookmarks, hits and kudos, especially for Jensen/Jared (12% of mpreg fics, but 26% of the hits go to those stories!) and Harry/Snape stories (14% of mpreg fics, but they attract 34% of the hits!).


Is it due to the fact of the mpreg component of those fics, or because the authors who write them are per se more popular authors? It is a difficult question to answer but if we look at the 594 authors that published both mpreg and non-mpreg stories in 2015, 70% of them received more hits on average for their mpreg fics than for their non-mpreg fics. For these authors, mpreg stories counted on average 10422 hits and non mpreg stories 6000 hits.

Hits, bookmarks and kudos could also certainly be influenced by various criteria:

  • length: longer fics tend to receive more hits and kudos
  • publication date: the longer the fic is online, the more it is read
  • status: complete or in progress
  • rating: explicit stories receive more hits and kudos

A simple linear regression allows to disentangle all these effects. The linear regression allows to estimate the effect of an independent variable on a dependent variable, controlling for the effect of other variables. Controlling for rating, date of publication, story length, status and warnings (underage, rape or non-con, graphic depictions of violence and major character death), being labeled “mpreg” increases the amount of hits received by 5230.

Screen Shot 2016-09-04 at 15.47.27

As expected, G, T and M ratings decrease the amount of hits with respect to being rated E (the reference category). The more recent a fic is, the less hits it has (being published one day later decreases the amount of hits by 2.6). Each word adds 0.06 hits. Being labeled “In progress” gives a small penalty in terms of hits (-375). Having “Underage” as a warning adds 1187 hits, whereas “Graphic depictions of violence” and “Major character death” are warnings that decrease the number of hits received. The “Rape Non Con” warning has no significant effect on hits.

Adding controls for fandom and ship complicates the results because there are so many fandoms and ships, most with very few fics (and subsequently no mpreg!).

If we restrict the sample to those major fandoms (Supernatural, One Direction, Harry Potter…) with a significant amount of mpreg fics, the effect of the mpreg label on hits remains quite similar.

Here are the regression results for fics from the 9 major ships having mpreg stories (Bilbo Bagins/Thorin Oakenshield being the reference category).

Screen Shot 2016-09-04 at 15.52.30

The estimated effect of being tagged mpreg is an additional 5430 hits.

A note: the coefficients vary much for each ship. Why are hits so much lower for SPN stories (Destiel or Jensen/Jared) than for Bilbo/Thorin? I just discovered that hit count varies A LOT by fandom. I found it very surprising that the average hit count for Supernatural fics is pretty low (3197) close to Glee (2944) and Transformers (2236). It is a stark contrast with Teen Wolf stories, that exhibit as much as 9424 hits on average per 10K+ fic. I don’t have precise ideas on how to explain those variations right now, maybe the subject of a future post…

Anyway, around 5000 additional hits is a very substantial effect. The average fic of more than 10K words published on A03 in 2015 had on average 3920 hits. The median number of hits was 1474 (the data was collected in May 2016).

So, mpreg even if a very minor genre, is highly popular. It attracts readers, other things being equal. But what does it talk about, other than the – not so – simple fact of men being pregnant? And how actually do those fictional men become pregnant?

Mpreg and A/B/O

It sures varies depending on the fandom, and especially on the potentialities offered by the canon universe. The Harry Potter and Bilbo/Lord of the Rings universes have magic. Loki can shapeshift and has given birth in Norse mythology. Those fandoms usually rely on those traditional explanations to give context to mpreg. On the contrary, in other fandoms, mpreg is closely linked to the A/B/O universe.

Only 2% of Harry Potter mpreg fics are tagged A/B/O, whereas at least 46% of SPN mpreg fics and 60% of Sherlock mpreg fics take place in the A/B/O universe.

Percentage of mpreg stories labeled A/B/O by fandom

If one runs a principal component analysis (PCA) on the labels used by the different ships, the first axis is indeed the opposition between AU and A/B/O.

Here is a representation of the two main dimensions of such PCA analysis.

  • In black: the 9 ships taken into account in the analysis
  • In blue: the 15 most important tags for explaining the differences between those ships

The arrows Alpha/Beta/Omega dynamics, Knotting and Mating cycles are actually leading in the direction of the first axis. It opposes the ships with few A/B/O (Loki/Thor, Harry/Snape, Bilbo/Thorin, Draco/Harry) to the others. We find in the far right the ships with lots of A/B/O: Jensen/Jared, Castiel/Dean, Sherlock/John.


The vertical axis is less important (19.6% of variance explained versus 28.9% for the first dimension). It opposes more violent ships (Jensen/Jared, Loki/Thor, Harry/Snape) to more fluffy ones (such as Harry Styles/Louis Tomlinson).

So, Mpreg is in some fandoms really interlinked with the A/B/O verse. Overall, 22% of mpreg stories are labeled with tags pertaining to the A/B/O verse. 28% of the stories taking place in the A/B/O verse are labeled mpreg (which is huge).

Here are the 12 fandoms with more than 20 stories of 10K+ words taking place in the A/B/O verse in 2015.


Unsurprisingly, Teen Wolf is the first fandom in terms of stories and share of A/B/O. These stories are pretty popular: they represent a high share of bookmarks, kudos and hits. But mpreg has little place in Teen Wolf A/B/O stories, compared to what happens in the Supernatural or Hobbit fandoms.


Mpreg seems pretty popular in A/B/O stories, especially for Hannibal readers. The counter example is Sherlock, where non-mpreg A/B/O stories have more readers and kudos than mpreg ones.

What have we learned?

  • Mpreg fics, even if only a small subset of stories, are very popular. They have more readers than the others, even when we take into account the fandom or the ship they are written in, as well as story characteristics (length, rating, etc.)
  • In many fandoms, mpreg is linked with the A/B/O universe. But even within the A/B/O verse, which is in itself a popular genre, mpreg attracts a disproportionate amount of readers
  • Some fandoms, however, disconnect totally mpreg and A/B/O. Harry Potter is the more striking example of it, magic giving an appropriate background for the possibility of male pregnancy

Constructive comments are welcome and appreciated! 🙂

Did you know about mpreg, and if yes, how? Do you read it? Are you repulsed by it? Do you write it? Was your feeling about the proportion of mpreg stories and their popularity in your favorite fandom close to the numbers depicted there?

As of now, we took into account only fics longer than 10K words published in 2015. Since mpreg fics tend to be longer than other fics, it is quite possible that the numbers presented here are higher than what would be if we had included shorter fics.

If you want to learn more about how we got all our data, please read here.

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