"Is intelligence mom, and adolescence dad's fault?"... How parental genes influence children 'like this'

Human characteristics and functions are determined by the complex interaction of genes and environmental factors. Genes are inherited from parents, and approximately 20,000 genes contribute to all traits, including appearance, health, personality, and physiological characteristics. Some of these are determined by a single gene, while others are influenced by multiple genes and environmental factors. The inheritance patterns of genetic traits are mainly divided into dominant genes, recessive genes, and X-linked inheritance.

X-linked genes are involved in intelligence and sex differences... mothers have a greater influence

Intelligence is a genetic trait associated with the X chromosome, and research shows that mothers have a greater influence on their children's intelligence. Men have only one X chromosome, while women have two, so women are more likely to pass on intelligence-related genes to their children.

In 2006, the Glasgow Medical Research Committee in Scotland conducted a study involving 12,686 individuals aged 14 to 22, and found that the children's IQ scores typically differed from their mothers' IQ scores by within 15 points on average. This demonstrates that a mother's intelligence is a major factor in determining her child's intelligence.

However, intelligence is not determined solely by genetic factors. According to twin studies, about 40% of intelligence is determined by genetics, while the remaining 60% is influenced by environmental factors such as education, nutrition, and health.

Early puberty and the MKRN3 gene... more influence from the father's gene

The manifestation of early puberty is closely related to mutations in the MKRN3 gene inherited from the father. A study published in the New England Journal of Medicine in 2013 revealed that this gene plays a role in suppressing puberty, and when mutations occur, the onset of puberty occurs prematurely.

This study was conducted through genomic analysis of 32 individuals from 15 families who experienced early puberty. Mutations in the MKRN3 gene were found in all 15 individuals, and all of these mutations were inherited from their fathers.

ADHD and serotonin... maternal genetic traits

Attention Deficit Hyperactivity Disorder (ADHD) is related to the mother's genetic traits. In particular, there is research indicating that children are more likely to experience ADHD if their mother has low serotonin levels.

A study published in JAMA Psychiatry in 2010 found that mutations in the TPH1 and TPH2 genes related to serotonin production lower serotonin levels, and children of mothers with these mutations were 1.5 to 2.5 times more likely to have ADHD. Serotonin is a neurotransmitter that plays a crucial role in regulating mood, sleep, and digestion.

Insomnia is more influenced by the mother's genetics.

Insomnia is also highly likely to be inherited from the mother. A study published in the 2023 Journal of Child Psychology and Psychiatry found that children of mothers with insomnia are more likely to experience insomnia themselves. About 35% of insomnia patients have a family history, and the family member most affected is the mother.

Insomnia does not occur due to a single factor; it results from the complex interaction of genetic and environmental factors. While a mother suffering from insomnia does not necessarily mean her child will experience the same issue, the risk may be increased.

Research on intelligence, adolescence, ADHD, and insomnia demonstrates how genetics influence various human traits. Genes and environment are crucial factors in human development; even if certain traits are genetically determined, they can be reinforced or weakened by environmental factors.