We are not puppets at the mercy of our genes
This 'epigenetic inheritance' may have a key bearing on the child's mental health (4, 7) and intellect (8–10). Although monozygotic twins are epigenetically identical in their early years, it is possible later in life to determine locus-specific variations in DNA methylation and histone acetylation as an expression of epigenetic differences. The influence of upbringing and environment therefore manifests itself in the gene expression (3).
Which environment are we referring to? The uterus carrying the fertilised egg is now defined as a highly sensitive environment, of crucial importance for development of disease in the child in later life (6), (11–14). The intrauterine environment is also dependent on the state of mind (6, 11) and lifestyle (4, 7) of the pregnant mother.
Characteristics such as cognitive function, i.e. the capacity to learn, understand, solve problems and think critically, are influenced by the woman who bears and rears the child. It is estimated that 40 – 60 % of these cognitive functions are genetically inherited (8), i.e. from the biological mother who donated the egg. The remaining 40 – 60 % will be dependent on stimuli from the mother who carries the child in utero, and breastfeeds and cares for the child after the birth, especially in the neonatal period (4).
The environment will also have a more decisive bearing than the egg donor on the child's mental health. Mental illness is strongly related to the environment to which the child is exposed, for example by its parents (7). It is therefore irrational to think that we are 'puppets' at the mercy of our genes. The pregnant mother will have a significant influence on the child's characteristics and development.
Epigenetics has provided a biological basis for mental health that unites body and soul to provide an integrated understanding of human health and behaviour, writes Linn Getz in the Journal of the Norwegian Medical Association (15). This knowledge is therefore essential for the development of the child's personality and intellect.
When an egg is donated, this means that the social mother, who has nurtured the fertilised egg until the birth and has breastfed and raised the child, has imparted to the child a biological similarity to herself. In part, she has in fact become a biological mother. Just as in the case of monozygotic twins, this initial phase is also important for the later development of phenotypic characteristics (3).