A really unethical experiment to establish the strength of the relationship between genotype and phenotype

Adopted twin studies are like gold for genetics research. They enable
the genetic predisposition to be compared. I've read stuff in one of
Oliver James books where adopted twins brought up in two totally
different families from birth had things in common such as flushing
before and after they went to the toilet.

Genetics research already values twins. They have the most number of
genes in common (the monozygotic ones anyway). But if they're brought up
in the same environment, i.e. with their natural parents, then their
influence makes it harder to determine what is genetics and what is
upbringing. Theories in the late 20th century point to schizophrgenic (I
forget how the word is spelt) or refrigerator mothers who were the
reason for schizophrenic offspring. As you might imagine this
perspective quickly fell out of favour however there may be a grain, or
perhaps a sand pit, of truth.

Kraeplin or Bleuler noted characteristics in children who were taken
away from schizophrenic mothers. Damn it. Wish I could remember where I
read that.

What I'm talking about though is totally horrible. I'm talking about
taking twins away from schizophrenic or manic depressive parents (on the
current evidence these two disorders have the same genetic root) then
assigning them to two very different families in very different
cultures. This needs to be done lots to get a large sample size and
compensate for random effects and biases. This could be the most
unethical experiment in history though there have been some pretty
terrible ones like Dr Money's one to work out how strong nature or
nuture were (a child who accideently had his penis electrocuted off in a
circumscion accidient was made to think he was a girl, brought up as a
girl and had his genitals surgically altered to make him think he was a
girl. It is a sick and interesting experiment. The guy shot himself
around the age of 33.

There are cases and papers on adopted twins. I've not had much luck
finding the ones for schizsophrenia and bipolar though. These would be
the best subjects to establish the true level of genetics versus
upbringing. It's sad to note that many severely mentally ill women may
have their children taken into care.

Once this is established it's the first step to discovering the
different genetic types of human being. This will be a fascinating
exploration, to understand us through our genes as well as through the
environmental factors (upbringing, schooling,life expieriences, local
culture etc). This would be the first step to ensuring genetic knowledge
isn't used to wipe out a type of human being, one that is part of the
human race but isn't udnerstood or appreciated in 2010 (but may be in 3010).