C is for Chimera

Our C word for today is chimera, a rare and interesting intersex condition.  Chimeras occur when fraternal twins fuse together in utero at an early stage of development.  The result is one individual with two different sets of DNA.  Some groups of cells in their body have one set of DNA, and other groups will have another set.

It is important to realize most chimeras are not intersex.  If both twins are the same sex, obviously they will not be.  Even if the twins where different sexes, chimeras DNA tends to stay within different organs and systems, having a male liver and female kidneys for example.  Thus even if they genetically have male and female cells, they usually develop along the lines of whichever genetics their reproductive system is.  That being said, there are rare cases where a chimera will have ambiguous genitalia and a mixed genetic reproductive system.

It is interesting.  Many people assume this is how all intersex people came to be.  My mom even said when I was a baby, people hypothesized that I was twins (I’m not).  Chimeras seem to play into an old cultural myth that a “hermaphrodite” must essentially be two people, or have some sort of soul or essence of two people (look up two spirit).  Obviously this doesn’t reflect reality at as most intersex persons are not chimeras and most chimeras are not intersex (in fact most chimeras don’t know they are chimeras).