twibling

plural twiblings

1. One of multiple biological siblings being carried by different surrogate mothers.

   Both pregnancies proceeded healthily, and Kate gave birth in July 2024, followed four months later by Ava delivering their second baby, resulting in a phenomenon known as “twiblings”.

   [2025 June 14, Erin Clark, People, archived from the original on 15 Jun 2025

   2 more examples

   When people press me about their status (“But are they really twins?”), the answer gets long. The word “twins” usually refers to siblings who shared a womb. But to call them just “siblings” instead of “twins” also raises questions because full genetic siblings are ordinarily at least nine months apart. And our children could be considered the same age because they were conceived at the same time (in the lab) and the embryos were transferred at the same time. If the person continues to quibble about whether they really qualify as twins (as, surprisingly, people often do), instead of asking why it matters, I announce airily that they are “twiblings.”

   2010 December 10, Melanie Thernstrom, The New York Times, archived from the original on 09 Jul 2015

   At first, Bi and Valdeiglesias considered implanting two embryos at once to have twins. Bi's fertility doctor strongly discouraged that because of risks to the babies and surrogate. Instead, Bi and Valdeiglesias settled on "twiblings" gestated by separate women but born a few weeks or months apart. […] Sheel Mohnot, a venture capitalist friend of Bi’s who has commissioned twiblings, said the problem is that information is siloed when “each agency has their own database of wombs.”

   2025 September 3, Emi Nietfeld, Wired, archived from the original on 03 Sep 2025