One feature of your phenotype is inherited not by a single gene or multiple genes but by a single pair of chromosomes
Humans have 23 pairs of chromosomes
In 22 cases, each chromosome in the pair is a similar shape
Each one has genes carrying information about the many different characteristics of your body
One pair of chromosomes is different - these are the sex chromosomes and they determine the sex of offspring
In human females the sex chromosomes are the same (XX)
In human males the sex chromosomes are different (XY)
The Y chromosome is very small and carries few genes other than those related to sexual characteristics
When the cells undergo meiosis to form gametes, one sex chromosome goes into each gamete
Human egg cells contain an X chromosome
Half of the sperm also contain an X chromosome and the other half contain a Y chromosome
The inheritance of sex can be shown using a Punnett square
