During conception (fusion of maternal and paternal germ cells) a new entity is formed,
which has individual structure and functions. From its gene-pool (genome) epigenetic
regulation selects those genes which are durably or acutely working, supplying a theoretically
lifelong program. However, this program could be changed spontaneously or artificially,
and there are life periods when the spontaneous changes are especially frequent and
the sensitivity to physiological or artificial (man-made) factors is high. The basic
sensitive (most vulnerable) period is the perinatal one, when the program agglomerated
(and this is manifested in the faulty hormonal imprinting and DOHaD theories: perinatal
adverse effects can cause diseases in adults), however, later periods are also sensitive.
Such rather sensitive periods are the puberty and periadolescence as well as weaning,
nevertheless, in any periods of life, cells or cell groups could be epigenetically
imprinted, if the cells are in the state of differentiation, independent of the age
or developmental state of the complete organism. Earlier mainly natural molecules
(products of volcanic eruptions or phytoestrogens, mykotoxins, tobacco) threatened
the program, today man-made artificial molecules (endocrine disruptors) can reprogram
the visibly stable program, by a single encounter with hormone receptors at the periods
of sensitivity (faulty hormonal imprinting) with life-long consequences (altered cell
functions, inclination to diseases, manifestation of diseases, etc., provoked by functional
teratogens). The deformed program is inherited to the offspring generations, where
further program transformations are taking place on the inherited (transformed) program.
As the amount and variants of man-made endocrine disruptors are enormously growing
in the human environment and its important parts act during the developmentally most
sensitive periods, the diseases provoked by them in adults expectedly will be enormously
accruing.
