Expectant parents often find themselves speculating about their future child’s traits, from height and intelligence to physical appearance.

After a baby is born, discussions about which parent they resemble often become a hot topic. Here’s a closer look at how genetics play a role in determining a baby’s characteristics and which parent contributes more to specific traits.

Who Decides the Baby’s Appearance: Mom or Dad?

Height: A Balanced Contribution

Under favorable nutritional conditions, genetics determine 70% of a child’s height. The contribution is evenly split, with 35% attributed to the father and 35% to the mother. If both parents are shorter, the remaining 30% of height potential depends on environmental and lifestyle factors.

Intelligence: A Greater Role for Mom

Intelligence is influenced by genetics, environmental factors, nutrition, and education. Genetic contributions to intelligence are estimated at 50%-60%, with maternal genes playing a more significant role, especially for male offspring. This is because many intelligence-related genes are carried on the X chromosome, of which mothers contribute one to sons.

Gender: Dad’s Contribution

A baby’s gender is determined by the father. The seeds carrying either an X or a Y chromosome combines with the mother’s X chromosome. An X results in a girl (XX), while a Y results in a boy (XY). Thus, the type of seeds determines the baby’s gender.

Inheritance Explained || How do we inherit features from our parents?

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What Traits Are Inherited and How?

Skin Color

Skin tone follows the "multiplicative and average" genetic rule. Two darker-skinned parents typically have darker-skinned children, while mixed-tone parents often have children with intermediate skin tones.

Eyes

- Shape and Size: Larger eyes tend to be a dominant trait. If one parent has large eyes, the child has a higher likelihood of inheriting them.

- Eyelids: Double eyelids are dominant over single eyelids, increasing the chance of a double-eyelid child if one parent has them.

- Iris Color: Dark colors like black dominate over lighter shades such as blue or green.

Nose

Prominent noses with high bridges are dominant traits. Children of parents with at least one high-bridged nose are more likely to inherit this feature.

Other Physical Traits

Ears: Larger ears are dominant, and children with one parent having large ears often inherit this trait.

Jawline: A pronounced chin is strongly dominant, passing reliably to offspring.

Obesity: Genetic predisposition accounts for a 40%-53% likelihood of obesity if one or both parents are overweight.

Baldness: Baldness is a gender-linked trait, typically passed down from the maternal grandfather to male grandchildren.

Acne: A family history of acne increases the likelihood of the child developing the condition.

The Role of Genetics in Behavior and Personality

Personality

The father’s genetic influence on personality is often stronger. Fathers play a significant role, especially in shaping daughters' self-esteem and emotional development.

Fatigue and Temperament

Genes related to temperament and stress responses may be inherited from either parent, with environmental upbringing playing an equally crucial role.

Practical Implications

While genetics provide a foundation for many traits, environmental factors, such as nutrition, education, and lifestyle choices, significantly influence a child’s development. Traits like height and physique can be optimized through proper diet and exercise, while emotional and intellectual growth is shaped by nurturing and education.

By understanding these genetic influences, parents can better appreciate their child’s unique combination of inherited traits and create a supportive environment to help them thrive.