ONE of the risk-factors for schizophrenia is that someone in the family has developed the disease. Many other factors than genetic factors are involved in its pathogenesis (traumas, infections, social environment). Having a genetic risk-factor for schizophrenia, however, does not necessarily mean that your girlfriend or her progeny will develop the disease automatically. Genetically, a fetus must inherit the “schizophrenic” genes from its parent(s). This may/may not happen because a fetus receives only half of the father’s and half of the mother’s genes (23 chromosomes each). If “schizophrenic” genes are not among the randomly chosen halves, they won’t be inherited. If “schizophrenic” genes are among those that form the fetus, they will be inherited.





It is important to note that sometimes “schizophrenic” genes are not inherited at all. Instead, genes can become mutated from normal genes during the early stages of embryogenesis.





Persons who carry “schizophrenic” genes don’t normally have the illness automatically, but only a predisposition to have it. Schizophrenia is not a simple, inheritable illness where only a presence of “schizophrenic” genes is enough for developing the disease. That’s why there are a lot of patients with schizophrenia who don’t have any relatives who have also been diagnosed with the disease... and a lot of people who don’t develop schizophrenia although they do have relatives with schizophrenia.





About your questions; I can’t validate the statement about “skipping generations” because I couldn’t find any reliable data to confirm this. Statistically, there are less chance that people over 25 will develop schizophrenia. Even if you screen her genes and find “schizophrenic” genes, there are no guarantees that she or her children will/won’t develop schizophrenia.