[VxH]

>> You have nothing (and there is nothing) to support your position that there is a genetic bias towards chimerism

 

Really? 

Another possibility for the coexistence of the XX males and true hermaphrodites within the same family may be explained on the basis of inheritance of genes that predispose to chimerism. Many cases of sporadic true hermaphroditism have been shown to be on the basis of chimerism of 46,XX and 46,XY zygotes. In one pedigree, a mosaic 46,XX/XY hermaphrodite had a 46,XX brother (pedigree 2–15) (48). The proportion of 46,XY-bearing cells in the gonad may have been so great that the gonad of the 46,XX male was a testis. Gonadal mosaicism can be implied for the pedigree where two brothers are 46,XX true hermaphrodites with male phenotype, one carrying a paternally transmitted marker, possibly of Y chromosomal origin and the other not (pedigree 2–16) (49).

 

http://jcem.endojournals.org/cgi/content/full/85/2/483

 

 

[ahayes]

I applaud you. You actually have some grounds for the suggestion. But this is proposed by the authors just as an untested hypothesis and in my earlier search I found nothing regarding a genetic predisposition.

At any rate as these cases are so rare and in most cases siblings of a chimeric person are normal and so is that person's offspring, there is no excuse to try to keep them from propagating.

I think you greatly underestimate environmental effects in placing so much importance on genetics. Many birth defects result from environmental causes such as illness of the mother (rubella), absence of necessary nutrients (spina bifida), or presence of foreign chemicals (thalidomide).