- Sex is inherited by sex chromosomes.
- 2 xx chromosomes make a female, one xy chromosome makes a person male
- Half of the sperm contain x chromosomes and the other half contains a y.
- The type of chromosome that fuses with the egg determines the gender of the zygote (to be baby) – therefore there is an equal chance for both genders
- When drawing a punnett square, females are homozygous, as they have XX chromosomes – they only have one column.