Sex Determination
Biology: Cambridge International GCSE Supplement, topic 17.3.3
Sex Determination
Healthy human body cells contain 23 pairs of chromosomes, only one of which is responsible for determining sex (or gender). This pair of chromosomes are called the sex chromosomes and can either be X or Y:
Females
Females are XX, so an egg contains one X chromosome.
Males
Males are XY, so a sperm contains either one X or one Y chromosome.