Boris and Sarah Sidis created an environment saturated with intellectual stimulation. They employed direct instruction methods, focusing on reading, languages, and mathematics from a very young age. This undoubtedly contributed to William's extraordinary early intellectual development.

Critics argue that the intense focus on intellectual pursuits may have come at the expense of social and emotional development. William lacked opportunities for typical childhood experiences and peer interactions, potentially contributing to his later difficulties with social relationships.

The high expectations placed on William by his parents, coupled with the resulting media attention, created immense pressure. This pressure may have contributed to his desire to withdraw from public life and his subsequent struggles with mental health.

As an adult, William became estranged from his parents, blaming them for the pressures he faced and their decision to commit him to a sanatorium. This estrangement suggests a deep resentment towards their parenting methods and their perceived control over his life.