Human development is the result of the comprehensive influence of many factors, and it is the unity of the interaction of congenital inheritance and acquired social influence and the subjective initiative of the subject in activities. The basic characteristics of people's physical and mental development are not the result of one of them acting alone. Whether it is genetic determinism or environmental determinism, it is one-sided to emphasize one factor and deny the role of other factors.

Genetic determinism unilaterally emphasizes the role of gene quality and ignores the interaction of other factors in people's physical and mental development, and falls into idealism.

Environmental determinism exaggerates the role of environment and education, denies the heredity of physiology and human subjective initiative, and falls into mechanical materialism.

Two-factor theory is a mixture of genetic determinism and environmental determinism. Although the one-sidedness of these two theories is avoided, the role of heredity and environment is equated, and the dialectical relationship of various factors affecting human development is not recognized. At the same time, the two-factor theory also denies human subjectivity and obliterates the leading role of education, which is also unacceptable.