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There's a short science book called Hidden Guests, it talks about why women have the potential to end up with microchimeric "incursions" from sexual partners an

There's a short science book called Hidden Guests, it talks about why women have the potential to end up with microchimeric "incursions" from sexual partners and their own fetuses, fetuses can have microchimerism with each other (not just twins but prior fetuses from same mother) and fetal cells crossing into the mother and towards the end talks about the resemblance between this and transplants( someone else's cells thriving in one's body). So if organ transplants can potentially have that effect, it's already happening to sexually active women, with the caveat that for the fetal cells it wouldn't have much formed personality, yet.

nickpsecurity 8mo ago
I found a good review of it: https://undark.org/2025/11/28/book-review-hidden-guests/ https://undark.org/2025/11/28/book-review-hidden-guests/
Terr_ 8mo ago
That reminds of a piece which frames pregnancy as a biochemical cold-war between the body of the mother and the child, which can turn "hot" to the detriment of both. In this framing, the chimerism isn't just from cells getting lost, it's the legacy of structured infiltration and sabotage. ______________ > In primates and mice, it’s a different story. Cells from the invading placenta digest their way through the endometrial surface, puncturing the mother’s arteries, swarming inside and remodelling them to suit the foetus. Outside of pregnancy, these arteries are tiny, twisty things spiralling through depths of the uterine wall. The invading placental cells paralyse the vessels so they cannot contract, then pump them full of growth hormones, widening them tenfold to capture more maternal blood. > These foetal cells are so invasive that colonies of them often persist in the mother for the rest of her life, having migrated to her liver, brain and other organs. There’s something they rarely tell you about motherhood: it turns women into genetic chimeras. https://aeon.co/essays/why-pregnancy-is-a-biological-war-between-mother-and-baby https://aeon.co/essays/why-pregnancy-is-a-biological-war-bet...

nickpsecurity 8mo ago

I found a good review of it: https://undark.org/2025/11/28/book-review-hidden-guests/ https://undark.org/2025/11/28/book-review-hidden-guests/

Terr_ 8mo ago

That reminds of a piece which frames pregnancy as a biochemical cold-war between the body of the mother and the child, which can turn "hot" to the detriment of both. In this framing, the chimerism isn't just from cells getting lost, it's the legacy of structured infiltration and sabotage. ______________ > In primates and mice, it’s a different story. Cells from the invading placenta digest their way through the endometrial surface, puncturing the mother’s arteries, swarming inside and remodelling them to suit the foetus. Outside of pregnancy, these arteries are tiny, twisty things spiralling through depths of the uterine wall. The invading placental cells paralyse the vessels so they cannot contract, then pump them full of growth hormones, widening them tenfold to capture more maternal blood. > These foetal cells are so invasive that colonies of them often persist in the mother for the rest of her life, having migrated to her liver, brain and other organs. There’s something they rarely tell you about motherhood: it turns women into genetic chimeras. https://aeon.co/essays/why-pregnancy-is-a-biological-war-between-mother-and-baby https://aeon.co/essays/why-pregnancy-is-a-biological-war-bet...