The risk of passing on genetic illness, disease and deformity is vastly increased with poor health of the mother and father who conceive the child.
Mothers in poor health (and fathers) will almost always pass on some physical restriction to their child albeit sometimes mild (such as childhood asthma or eczema in cases when the health is not as bad) to very severe (such as autism and low iq/physical and mental disability) when the health is very poor.
Mothers (and fathers) can improve their health markedly by addressing deficiencies either before, during and after conception (for the mother only).
Deficiency meaning those of blood, yin, yang or qi rather than one particular vitamin or mineral per se, although there is some overlap with blood and iron or B12, yin and magnesium, yang and Qi and B complex or other Co-factor vitamins and minerals however this is a generalisation and all persons are different.
Meditation over time brings better health and can offset genetic chance however if the person generally does not feel good within themselves and happy and healthy (as a lasting enduring feeling denoting health of spirit) then it can be presumed that there is more work to be done.