There’s a window of time in our lives we’ve all passed through yet still know so little about: early gestation. Researchers have found a pair of genetic deletions associated with schizophrenia that likely occur in that formative period.

The discovery comes from a team of researchers led by Harvard Medical School clinician-scientist Eduardo Maury, who combed through genetic data from blood samples of nearly 25,000 people with or without schizophrenia.

While the two genetic alterations need further validation, the findings strengthen an emerging idea that the seeds of schizophrenia aren’t always inherited, yet still may be acquired long before someone meets the world.