Which parent has a greater influence on a son's intelligence?

A child’s IQ is influenced by the genes of both parents; there is no single determining factor. The inheritance of intelligence involves polygenic complexity, primarily involving genes linked to the X chromosome, the expression of autosomal genes, and the interaction with environmental factors.

The X chromosome carried by mothers contains a large number of genes related to cognitive functions, which may have a direct impact on the intelligence of boys. Studies have shown that genes such as FMR1 and MAOA on the X chromosome are closely related to neural development. Maternal mitochondrial DNA also influences neuronal function through metabolic pathways related to energy production. However, the autosomal genes provided by the father also play a role in crucial processes such as the development of the cerebral cortex and synaptic plasticity. For example, the NRG1 and COMT genes have a significant regulatory effect on the development of the prefrontal lobe.

Environmental factors can contribute 40% to 60% to intellectual development. The nutritional status of the mother during pregnancy directly affects the proliferation of fetal brain cells, and deficiencies in nutrients such as folic acid and DHA can cause irreversible damage. The quality of the family environment provided by the father is equally important, including the investment in early education and the frequency of parent-child interactions. The nurturing environment created jointly by both parents regulates gene expression through epigenetic mechanisms, and this dynamic interaction far exceeds the influence of purely genetic factors.

It is recommended that both partners work together to improve their health during the preconception period. During pregnancy, attention should be paid to a balanced diet and fetal development. After birth, it is important to provide an environment rich in cognitive stimuli for the child. Regular assessments of children's development should be conducted to identify any abnormalities and intervene promptly. The development of intelligence requires the combined action of both genetic factors and environmental nurturing; attributing it solely to one of these aspects does not conform to scientific understanding.