X Chromosome, Y Chromosome
Sex Differences and Fetal Development
X and Y chromosomes determine not only the sex of an individual, but many broad characteristics as well. From grip-strength to aggression , there are myriad differences between men and women beyond simply their sexual organs. This is known as sexual dimorphism and is found in most species.
In vitro fertilization (IVF) technology exists that can allow parents to select their baby’s gender—for a price. It’s possible to separate X and Y-sperms by flow sorting with some degree of accuracy. In the future, fertilization may not be so random after all, but while pre-selection may be important to prevent certain life-threatening, inherited conditions, it involves a slippery ethical slope that requires further investigating.
X chromosomes are expressed differently depending on whether you are male or female. Since females have two X chromosomes, one may be expressed, or manifest in the phenotype, and the other may be silenced. Because males have only inherited one X chromosome, it is sure to be expressed.
The X chromosome carries at least 150 genes linked to intelligence. Since the mother has two X chromosomes to pass along while the father only has one, the mother’s contribution to the child’s intelligence will, on average, be greater than the father’s; this is especially true if the child is male, since his only X chromosome will come from his mother.
Explore More About X Y Chromosomes
For a comprehensive understanding of x y chromosomes, read our complete guide: