Avian Female Sex Determination - Anatomy & Physiology

• Females are the heterogametic sex, with one copy each of the Z and W sex chromosomes.
• Males are homogametic (ZZ).
• Not clear whether it is the presence of the female-specific W chromosome that triggers female development, or the dose of Z chromosome that confers maleness.
• Female’s egg rather than the male’s sperm determines what sex the chick will be. Thus the female has the potential to determine the sex of her young by whether she ovulates male or female eggs.