Miscarriages... More likely with girls?

I can’t help but observe that I know the gender of 5 of my pregnancies.  My son and the last four transfers we have done, which are all girls.

And only the boy made it.  (So far, we’re still waiting on the last girl.)

I’ve been wondering—is that a sign?  Am I not meant to be the mom of a daughter?  Or is it possible there’s an unknown reason—like something genetic related only to girls?  Or is it just dumb luck?

Maybe it’s because females are more likely to miscarry.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3150206/

This article suggests that for women with recurrent miscarriages, 64% of the embryos were female:

“In total, 313 specimens were successfully karyotyped, with a median gestational age of 10 weeks at miscarriage (interquartile range 8–13); 199 (64%) were females and 114 (36%) were males. In total, 121 (39%) had abnormal karyotypes, the most prevalent of which were chromosome 21 and 16 trisomies, triploidy, and monosomy X.”

Because the minority of the miscarriages were related to chromosomal abnormalities… something else was going on.  This article suggests that “In our opinion, during the first trimester of pregnancy, miscarried female POC may be partially due to imprinted paternal genes.”

I’m sorry—what now?  

I had to go to Wikipedia.  (https://en.wikipedia.org/wiki/Genomic_imprinting) It’s complicated, but from what I can gather from the article, some women’s bodies may just prefer male embryos.  (We’ve all known that couple that decided for a third… or fourth… because they wanted a daughter, only to end up with yet another boy.)

This article also recognizes the fact that miscarriages are more likely to be female:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4130929/

And here’s another article noting the same thing:

https://www.theguardian.com/science/2015/mar/30/female-embryos-more-likely-to-die-in-pregnancy-than-males-study-claims

It suggests, “Female embryos could be at greater risk due to the way X chromosomes are inactivated in cells, scientists said. Females have two X chromosomes, but one is randomly switched off in each cell, leaving just one with active genes. However, sometimes this process becomes unbalanced and one X chromosome begins to dominate all the body’s cells. If there are genetic flaws on the dominant chromosome, it can lead to fatal health problems.”

Maybe my uterus wants boys.  We’ll see if this girl makes it (I’m not feeling optimistic).