As regards to intraocular retinoblastoma, which one of the following statement is FALSE?

Retinoblastoma is the most common intraocular malignancy of childhood. . 90% of patients with newly diagnosed retinoblastoma are sporadic and 10% of cases are familial. All patients with familial retinoblastoma are at risk to pass the predisposition for the development of the tumor to their offspring. About 25% of sporadic unilateral cases are heritable. Hereditary form of retinoblastoma, is diagnosed earlier than the non hereditary form of the disease, it carries a risk of other malignancies and can affect the offspring of the affected individual. The non hereditary form of the disease is unilateral, the children of affected individual are normal and this form of disease is not associated with increased risk of other malignancies. Ref: Genetic Diseases of the Eye edited by Elias I. Traboulsi page 829, Perez and Brady's Principles and Practice of Radiation Oncology, Page 438 edited by Edward C. Halperin, page 787.