Determining Sex in Humans a Very Complicated, Yet Intriguing Process

05 Oct 2017

Sex determination in humans is one of the most complicated and intriguing processes within the human development cycle. In order to identify the sex of an individual, it is necessary to analyze the composition and function of the chromosomes and genes.

Human chromosomes and genes form the body’s makeup and characteristics. Genes are segments of DNA (Deoxyribonucleic acid) that creates proteins for growth, digestion and energy production. Genes are also considered units of heredity. Chromosomes are threadlike strands of DNA that carry bundles of genes in linear order.

The process of sex determination

Sex determination is a result of two processes, namely, sex determination and sex differentiation. Sex determination is the process that controls the sexual pathway of the human baby, whether male or female. On the other hand, sex differentiation is a series of events that create the female or male phenotypes.

Humans have 43 chromosomes and are arranged in 23 pairs. The single pair determines the sex of the human baby and the remaining 22 pairs shape the body’s characteristics. Females have two copies of X chromosomes (XX) while the males have one copy of the X and Y chromosome (XY).

During fertilization, the new gamete inherits the mother’s X chromosome and forms with the X or Y chromosome of the father. The type of chromosome that will come from the father depends on the inherited chromosome of the sperm cell that is the first to enter the egg cell. As a result, the father’s sperm cell determines the sex of the human baby.

In addition, sex determination in humans takes place during the development of the gonad into a testes or ovary inside the womb. In the presence of a Y chromosome, there is an early embryonic development of testes at the tenth week of pregnancy. Alternatively, the absence of a Y chromosome results in the development of gonad into an ovary. However, chromosomes and genes are not enough to determine the sex of the human baby. In order to produce a male baby, sufficient exposure to testosterone is necessary during the development of the fetus.

Chromosomal pairings are not limited to XX and XY alone, as there are arrays of chromosome complements, hormone balances and phenotypic variations that should be considered. However, these things disrupt the normal composition of the sex chromosomes. These chromosomal functions result in genetic and development abnormalities or aberrations. Hermaphrodism, for example, is a birth abnormality in which an individual has inherited both the female and male sex organs. Another example is the XYY male disorder. In this condition, males will grow taller beyond the average height and will be predisposition to acne because of the high level of testosterones inside their body. These are just some examples of birth abnormalities.