Regarding the causes of schizophrenia

Consider the following facts regarding the causes of schizophrenia:

- For most people, the odds of developing schizophrenia are about 1 in 100. For those with a sibling or a parent with the disorder, the odds increase to 1 in 10.

- If the affected sibling is an identical twin, the odds are close to 1 in 2.

- Children of mothers who contract influenza during their pregnancy are more likely to develop schizophrenia.

- The Genain quadruplets (all of whom are genetically identical) have schizophrenia, but some are more severely affected than others.

Which of these facts is evidence for the role of nature? Which facts are evidence for the role of nurture? Which facts support an interaction between nature and nurture? Explain your reasoning for each.