The cause of the oncological diseases in children and the specific spectrum of this pathology, with hemangiomas prevailing among benign tumors (BT), and leukemia, lymphomas, and neural tissue tumors among malignant neoplasms (MN), remains unknown. The authors studied the similarities and differences of the connections between environmental factors, benign tumors and MN, as well as the relations between BT and MN. The causality of the so-called "sporadic" fluctuations in the incidence of neoplasms and their relations with environmental factors were revealed. A hypothesis of environmentally-induced alternative oncogenesis is suggested. According to the hypothesis, fetal hemoglobin enhances environmentally-related oxidative stress (EROS), leading to epigenomic regulation disorder of SEMA 7A and MICAL family proteins in the endothelium, axon growth cone, and hematopoietic stem cells. © The Authors, published by EDP Sciences, 2020.