During early embryonic development, XX females undergo a process of X-inactivation, where one X chromosome pair is randomly inactivated. This process allows for XY males and XX females to have the same number of X-linked genes expressed, neutralizing the difference in gene dosage (the number of gene copies in the genome).

X-chromosome inactivation (XCI)

Most human females have two X chromosomes, while most males have an X and Y chromosomal pair. 

Smith College

The scientific field of study of traits and their passage from parents to offspring. Humans inherit 23 chromosomes from the father, and 23 from the mother. These 23 pairs of chromosomes consist of 22 autosomal chromosome pairs and one sex chromosome pair. The physical unit of inheritance is a gene, comprised of DNA (Deoxyribonucleic acid) segments.

Genetics and Inheritance in Humans

Wikipedia

Allosomes (sex-determining chromosomes).

Molecular Anthropology studies molecular techniques to understand human evolution and how human biology is impacted by their environment, nutrition, and culture. These anthropologists also examine and compare evolutionary traits between ancient and modern humans and hominin ancestors. 

Learn Before

Related

Learn After