What Influences Babies’ Genetics?

January 16, 2019
If you're going to have a boy or girl, you might wonder what influences your baby's genetics. We'll tell you all you need to know in this article.

You’re probably very curious to know what your baby will be like. Will he be tall or short? Will he have blue, green or brown eyes? The questions you ask yourself are endless. Now, what really influences babies’ genetics?

Genetic and environmental influences

The expression “baby genetics” is determined by the following formula:

Phenotype = Genotype + Environment + (Genotype x Environment)

How is that? Genetic expression, called phenotype (eye color, size, weight, etc.) is determined by genetic factors, environmental factors (the environment) and the interaction between them.

However, you must understand that the environment can’t modify or alter certain genes, like physical appearance.

That is, if the genetics from parents determines that the baby’s eyes will be green, it doesn’t matter if the baby is born in China, Senegal or Argentina. The color of his eyes will be green.

what influences babies' genetics

Time and the environment can modify certain genes. However, they don’t necessarily express themselves. On the other hand, the environment influences the expression of certain genes that shapes babies’ personalities

Some genes can predispose them to smoke or drink alcohol, whereas others are easier to manage and control. They’re directly influenced by the environment.

Registration of genes

Both parents determine their baby’s genetics. These genes form babies’ eyes, nose, fingers, feet size, hair thickness, etc. Everything is recorded there. In addition, genes are stored in the chromosomes. 

Genes are units that contain all of a person’s information. Human beings have more than 20,000 genes.

Generally, people have 23 pairs of chromosomes. The father contributes half of the genetic information and the mother gives the other half.

Now, why are babies more like one parent than the other? Each gene is made up of two copies, one from the mother and one from the father.

The characteristic that finally expresses itself is the one that will dominate the other. Also, note that the human genome also responds to positive energy.

The health portal Medline Plus explains the following: “Each chromosome in a pair carries basically the same information. That is, each pair has the same genes. Sometimes, there are slight variations of these genes. These variations occur in less than 1% of the DNA sequence. The genes that have these variations are called alleles.”

what influences babies' genetics

What color will his eyes be?

For quite some time, researchers thought that only two genes determined a person’s eye color. However, given technological advances that allow deeper studies into the human genome and what influences babies’ genetics, we know that at least 8 genes determine eye color.

However, we know that brown is dominant over green and blue, and green is dominant over blue.

Dominant genes and recessive genes

Keep in mind that there are dominant genes and recessive genes. The first ones are the strongest, meaning they’re more likely to determine certain characteristics. 

Recessive genes, although weaker, are still there. Therefore, they may appear a few generations later.

And hair?

The case of hair is very interesting. Years ago, researchers defined 12 different genes that cause hair color. Between all of them, they have 45 variations on color, shape and type.

Dark hair is a dominant gene and blonde is recessive. Regarding redheads, parents must have this gene as recessive and that the two alleles have redhead information. This is very rare.

What influences babies’ genetics more?

The environment greatly influences babies’ genetics, specifically in the way their genes will finally express themselves. For example, a child may have a genetic predisposition to be tall and thin. However, if he doesn’t eat well during childhood, he may never express those genes.

The environment has the capacity to favor or make it difficult for certain genes to express themselves. It’s part of our job to help our baby enjoy a full life with the genes we’ve passed onto him.

  • Genética: MedlinePlus enciclopedia médica [Internet]. Medlineplus.gov. 2018. Disponible en: https://medlineplus.gov/spanish/ency/article/002048.htm
  • Yashon, R. K., & Cummings, M. R. (2010). Genética humana y sociedad. Cengage Learning Editores
  • Romeo, C. M. (1995). Genética humana: fundamentos para el estudio de los efectos sociales de las investigaciones sobre el genoma humano. Bilbao, España: Universidad de Deusto