Adoption Studies are also other methods to investigate the nature nurture approach. It is well established fact that the adopted children do not share the genetic constituents with the adoptive parents. Comparison of adopted children with biological and non biological parents can provide an understanding on the heritability of the traits.
Concordant characters between the adopted children and the non biological parents would be assessed as the influence of environmental factors. This method has been extensively used in analyzing the heritability of behavioral traits.
Adoption studies have shown that the children born out of schizophrenic parents and adopted by non schizophrenic parents have higher chance of developing the disorder than the children out of normal biological parents and adopted by the same (Pasternak, 2005).
This method has some limitations too as such studies require access to good adoption records and stable populations over generations, so there are a limited number of situations in which they can be used (Stanford et al., 2013).